SECTION 1. Start of Each Period

Article 1 - First and Third Periods

a. Prior to the game, during warm-ups, teams must remain in an agreed separate half of the field, normally the half up to the line five yards from midfield to their left, looking from their team area towards the field.
b. Each half shall start with a kickoff.
c. Three minutes before the scheduled starting time, the referee shall toss a coin at midfield in the presence of not more than four field captains from each team and another game official, first designating the field captain of the visiting team to call the coin toss. Before the second half, the referee will obtain the teams’ second half options.
d. During the coin toss, each team shall remain in the team area. The coin toss begins when the field captains leave the sidelines and ends when the captains return to the sidelines.

PENALTY − [d] Five yards from the succeeding spot [S19: IPR].
e. The winner of the toss shall choose one of the following options:
1. To designate which team shall kick off.
2. To designate which goal line his team shall defend.
3. To defer his selection to the second half.
f. The opponent shall then choose option 1 or 2 above, as available.
g. If the winner of the toss chooses option 3 above, then after the opponent’s choice the winner selects the available option (1 or 2 above).
h. For the second half, the loser of the toss, or the winner who chooses option 3 above, shall choose option 1 or 2 above. The opponent then chooses the remaining available option.

Article 2 - Second and Fourth Periods

Between the first and second periods and also between the third and fourth periods, the teams shall defend opposite goal lines.
a. The ball shall be relocated at a spot corresponding exactly, in relation to goal lines and sidelines, to its location at the end of the preceding period.
b. Possession of the ball, the number of the down and the distance to be gained shall remain unchanged.

Article 3 - Extra Periods

The tiebreaker system will be used when a game is tied after four periods. (Exception:  Competitions may adopt regulations to forgo the tiebreaker system if the scores are tied at the end of a regular season game. In that event, the game shall be terminated and the result shall stand as a tie.) IFAF football-playing rules apply, with the following exceptions:
a. Immediately after the conclusion of the fourth quarter, officials will instruct both teams to retire to their respective team areas. The officials will assemble at the midfield line and review the tiebreaker procedures.
b. The officials will escort the captains (Rule 3-1-1) to the centre of the field for the coin toss. The referee shall toss a coin at midfield in the presence of not more than four field captains from each team and another game official, first designating the field captain of the visiting team to call the coin toss. The winner of the toss may not defer the choice and must choose one of the following options:
1. Offense or defense, with the offense at the opponent’s 25-yard line to start the first possession series.
2. Which end of the field shall be used for both possession series of that overtime period.
c. The loser of the toss shall exercise the remaining option for the first extra period and shall have the first choice of the two options for subsequent even-numbered extra periods.
d. Definition. An extra period shall consist of two possession series with each team putting the ball in play by a snap on or between the hash marks on the designated 25-yard line (unless relocated by penalty); this becomes the opponent’s 25-yard line. The snap shall be from midway between the hash marks, unless the offensive team selects a different position on or between the hash marks before the ready-for-play signal. After the ready- for-play signal, the ball may be relocated only after a charged team timeout, unless preceded by a Team A foul or offsetting fouls.
e. Possession series. Each team retains the ball during a possession series until it scores or fails to make a first down. The ball remains alive after a change of team possession until it is declared dead. However, Team A may not have a first down if it regains possession after a change of team possession (A.R. 3-1-3:I-IX). Beginning with the fifth extra period, a team’s possession series will be one play for a two-point try from the three-yard line, unless relocated by penalty.
Team A and B designations are the same as defined in Rule 2-27-1.
f. Scoring. The team scoring the greater number of points during the regulation and extra periods shall be declared the winner. There shall be an equal number of possession series, as described in (e) above, in each extra period, unless Team B scores other than on the try. Beginning with the third extra period, teams scoring a touchdown must attempt a two-point try. Although not illegal, a one-point try attempt by Team A will not result in a score (A.R. 3-1-3:X).
g. Fouls after a change of team possession are treated specially (Rule 10-2-7). (A.R. 3-1-3:XI-XIV)
h. Timeouts. Each team shall be allowed one timeout for each extra period (Rule 3-3-7). Timeouts not used during the regulation periods may not be carried over into the extra period(s). Unused extra period timeouts may not be carried over to other extra periods. Timeouts between periods shall be charged to the succeeding period.
Radio and television timeouts are permitted only between extra periods (first and second, second and third, etc.). Charged team timeouts may not be extended for radio and television purposes. The extra period(s) begins when the ball is first snapped.

SECTION 2. Playing Time and Intermissions

Article 1 - Length of Periods and Intermissions

The normal total playing time in a game shall be 48 minutes, divided into four periods of 12 minutes each, with one-minute intermissions between the first and second periods (first half) and between the third and fourth periods (second half) (Exception: A one- minute intermission between the first and second and the third and fourth periods may be extended for radio and television timeouts).
Competitions or national federations may adopt regulations to set the maximum playing time in a game to 60, 48, 40 or 32 minutes, provided the four periods are of equal length.
a. No period shall end until the ball is dead and the referee declares the period ended [S14].
b. The intermission between halves shall be 20 minutes, unless altered before the game by mutual agreement of the administrations of both teams and the competition authority. Immediately after the second period ends, the referee should begin the intermission by signalling to start the game clock [S2].
c. It is strongly recommended that game management schedule the kickoff time no later than four hours before darkness (defined as the time of local sunset or the time at which any artificial lights must be switched off).
d. If a game (delayed by five or more minutes) kicks off less than 3½ hours before darkness, playing time shall be limited to a maximum of 48 minutes. (A.R. 3-2-1:I)
e. If a game (delayed by five or more minutes) kicks off less than 3 hours before darkness, playing time shall be limited to a maximum of 40 minutes. (A.R. 3-2-1:I)

Article 2 - Timing Adjustments

Before the game starts, playing time and the intermission between halves may be shortened by the referee if he is of the opinion that darkness or other conditions may interfere with the game. The four periods must be of equal length if the game is shortened before its start.
a. Any time during the game, the playing time of any remaining period or periods and the intermission between halves may be shortened by mutual agreement of the opposing head coaches and the referee. (A.R. 3-2-1:I)
b. Timing errors on the game clock may be corrected but only in the period in which they occur.
c. If the referee has positive knowledge of the elapsed time, he will reset and appropriately start the game clock.
d. Timing errors on a play clock may be corrected by the referee. The play clock shall start again (Rule 2-29-2).
e. When the play-clock count is interrupted by circumstances beyond the control of either team (without positive knowledge of game clock elapsed time), a new count shall be started and the game clock shall start per Rule 3-2-4-b.
f. The 40/25-second clock is not started when the game clock is running with fewer than 40 or 25 seconds, respectively, in a period.
g. The game clock should not be stopped if the play clock is started in conflict with paragraph f above.
h. Timing adjustments for games using video review are governed by Rule 12-2-2-a-10.

Article 3 - Extension of Periods

a. A period shall be extended for an untimed down if one or more of the following occurs during a down in which time expires (A.R. 3-2-3:I-VIII):
1. A penalty is accepted for a live-ball foul(s). (Exception: Rule 10-2-5-a). The period is not extended if the foul is by the team in possession and the statement of the penalty includes loss of down (A.R. 3-2-3:VIII).
2. There are offsetting fouls.
3. An official sounds his whistle inadvertently or otherwise incorrectly signals the ball dead.
b. Additional untimed downs will be played until a down is free of the circumstances in statements 1, 2 and 3 of Rule 3-2-3-a (above).
c. If a touchdown is scored during a down in which time in a period expires, the period is extended for the try (Exception: Rule 8-3-2-a).

Article 4 - Timing Devices

a. Game clock. Playing time shall be kept with a game clock that may be either a stop watch operated by the line judge, back judge, field judge or side judge, or a game clock operated by an assistant under the direction of the appropriate judge. The type of game clock shall be determined by the game management.
b. 40-Second Clock.
1. When an official signals that the ball is dead, the play clock shall begin a 40-second count.
2. If the 40-second clock does not start or the count is interrupted for reasons beyond the control of the officials or the play-clock operator (e.g. clock malfunction), the referee shall stop the game clock and signal (both palms open in an over-the-head pumping motion) that the play clock should be reset at 40 seconds and started immediately.
3. In the event that the 40-second clock is running and reads 20 before the ball is ready to be snapped, the referee shall signal that the play clock be set at 25 seconds. If there is a delay in doing this, the referee shall declare a timeout and signal that the play clock be set at 25 seconds. When play is to be resumed, the referee will give the ready-for-play signal [S1] and the play clock shall begin the 25-second count. The game clock will start on the snap unless it had been running when the referee declared a timeout; in that case, it will start on the referee’s signal (Rule 3-3-2-f). (A.R.3-2-4:I and II)
c. 25-Second Clock. If the officials signal the game clock to be stopped for any of the following reasons, the referee shall signal (one open palm in an over-the-head pumping motion) that the clock should be set at 25 seconds:
1. Penalty administration.
2. Charged team timeout.
3. Media timeout.
4. Injury timeout for a player of the offensive team only. The play clock is set to 40 seconds for an injury to a player of the defensive team.
5. Measurement.
6. Team B is awarded a first down.
7. After a kick down other than a free kick where Team B will next snap the ball.
8. Scores other than a touchdown (not the try).
9. Start of each period.
10. Start of a team’s possession series in an extra period.
11. Video review.
12. Other administrative stoppage.
13. An offensive team player’s helmet comes completely off through play. The play clock is set to 40 seconds if the helmet comes completely off a player of the defensive team.
When play is to be resumed, the referee will give the ready-for-play signal [S1] and the play clock will begin its count.
d. Device malfunction. If a visual 40/25-second timing device becomes inoperative, both coaches shall be notified by the referee immediately and both clocks shall be turned off.

SECTION 3. Timeouts: Starting and Stopping the Clock

Article 1 - Timeout

a. An official shall signal timeout when the rules provide for stopping the clock or when a timeout is charged to a team or to the referee. Other officials should repeat timeout signals. The referee may declare and charge himself with a discretionary timeout for any contingency not elsewhere covered by the rules. (A.R. 3-3-1:IV)
b. When a team’s charged timeouts are exhausted and it requests a timeout, the officials shall not acknowledge the request (Rule 3-3-4).
c. Once the game begins, players shall not practice with a ball on the field of play or the end zones except during the half-time intermission.

Article 2 - Starting and Stopping the Clock

If the margin in the score becomes more than 34 points, a running clock session will start. During a running clock session, the game clock will stop only for reasons marked * below. For other events listed here, the clock will keep running. Competitions may adopt regulations to:
1. forgo the running clock rule completely;
2. forgo the rule only in the first half of a game;
3. limit the running clock rule to use after an elapsed time no later than 2 hours 15 minutes after kickoff, but only in games that are broadcast live;
4. reduce the score margin below 34 points.
a. Free Kick. After the ball is free-kicked, the game clock shall be started on an official’s signal when the ball is legally touched in the field of play, or when it crosses the goal line after being touched legally by Team B in its end zone. It is subsequently stopped on an official’s signal when the ball is dead by rule. (A.R. 3-3-2:VII)
b. Scrimmage Down. When a period begins with a scrimmage down, the game clock shall be started when the ball is legally snapped. On all other scrimmage downs, the game clock shall be started when the ball is legally snapped (Rule 3-3-2-d) or on a prior signal by the referee (Rule 3-3-2-e). The game clock shall not run during a try, during an extension of a period or during an extra period. (A.R. 3-3-2:I-IV)
c. After a Score. The game clock shall stop on an official’s signal after a touchdown, field goal or safety. It shall be started again as in (a) above unless an accepted penalty erases the score or the down is repeated in which cases it shall be started when the ball is legally snapped.
d. Starts on the Snap. For each of the following, the game clock is stopped on an official’s signal. If the next play begins with a snap, the game clock will start on the snap:
1. Touchback (provided Team B will next snap the ball).
2. With fewer than two minutes remaining in a half a Team A ball carrier, fumble or backward pass is ruled out of bounds. (Exception: After a Team A forward fumble goes out of bounds, the clock starts on the referee’s signal.)
3. Team B is awarded a first down and will next snap the ball. (A.R. 3-3-2:V)
4. A forward pass is ruled incomplete.
5. A team is granted a charged timeout. *
6. The ball becomes illegal. *
7. A period ends. *
8. A legal kick down ends. (A.R. 3-3-2:VI)
9. A return kick is made.
10. A scrimmage kick is made beyond the neutral zone.
11. Team A commits a delay-of-game foul while in a scrimmage kick formation.
e. Starts on the Referee’s Signal. For each of the following reasons, the game clock is stopped on an official’s signal. If the next play begins with a snap, the game clock will start on the referee’s signal:
1. Team A is awarded a first down, either through play or by penalty.
2. A Team A forward fumble goes out of bounds.
3. Other than with fewer than two minutes remaining in a half, a Team A ball carrier, fumble or backward pass is ruled out of bounds.
4. To complete a penalty (Exception: Rule 3-4-5-b). *
5. An injury timeout is allowed for one or more players or an official. (A.R. 3-3-5:I-V)*
6. An inadvertent whistle is sounded.
7. A possible first-down measurement. *8. Both teams cause a delay in making the ball ready for play (A.R. 3-3-1:III).
9. A live ball comes into possession of an official.
10. A head coach requests a conference or video review. *
11. The referee grants a media timeout. *
12. The referee declares a discretionary timeout. *
13. The referee declares a timeout for unfair noise (Rule 9-2-1-b-5).
14. An illegal pass is thrown to conserve time (A.R. 7-3-2:II-VII) (Exception: Rule 3-4-5-b).
15. The referee interrupts the 40/25-second count.
16. A player’s helmet comes completely off through play.
17. When either team commits a dead-ball foul. *
f. Snap Supersedes Referee’s Signal. Whenever one or more incidents that cause the game clock to be started on the referee’s signal (Rule 3-3-2-e) occur in conjunction with any that cause it to be started on the snap (Rules 3-3-2-c and 3-3-2-d), it shall be started on the snap. (Exception: Rule 3-4-5 (10-second runoff) supersedes this rule.) (A.R.3-3-2:VIII-IX)
g. Running clock.

1. During a running clock session, the clock will always be started on the ready for play rather than the snap.  (A.R. 3-3-2:X-XI)
2. If during a running clock session, the margin in the score continues to be more than 34 points, the running clock session will continue. If the margin drops to 34 or fewer points, the running clock session will end immediately on the relevant score and normal clock rules will apply unless and until the margin becomes more than 34 points again. (Exception: If a competition reduces the score margin to start a running clock session below 34 points, the margin to end it will be similarly lower.)

Article 3 - Suspending the game

a. The referee may suspend the game temporarily when conditions warrant such action.
b. When the game is stopped by actions of a person(s) not subject to the rules, or for any other reasons not specified in the rules, and cannot continue, the referee shall:
1. Suspend play and direct the players to their team areas.
2. Refer the problem to those responsible for the game’s management.
3. Resume the game when conditions are satisfactory.
c. If a game is suspended under Rules 3-3-3-a and b before the end of the fourth period and cannot be resumed, there are four possible options:
1. Resume the game at a later date;
2. Terminate the game with a determined final score;
3. Forfeit of the game; or
4. Declare a no contest.
The option that takes effect shall be determined by competition regulations.
d. If a game is suspended under Rules 3-3-3-a and b after four periods of play and cannot be resumed, the game shall be ruled a tie. The final score shall be the score at the end of the last completed period. (Note: If a winner must be determined in a competition playoff game, competition regulations shall determine when and where the game will be resumed.)
e. A suspended game, if resumed, will begin with the same time remaining and under the identical conditions of down, distance, field position and player eligibility.

Article 4 - Charged Team Timeouts

When timeouts are not exhausted, an official shall allow a charged team timeout when requested by any player or head coach when the ball is dead.
a. Each team is entitled to three charged team timeouts during each half.
b. After the ball is declared dead and before the snap, a legal substitute may request a timeout if he is between the nine-yard marks. (A.R. 3-3-4:I)
c. A player who participated during the previous down may request a timeout between the time the ball is declared dead and the snap without being between the nine-yard marks. (A.R. 3-3-4:I)
d. A head coach who is in, or in the vicinity of, his team area or coaching box may request a timeout between the time the ball is declared dead and the next snap.
e. A player, incoming substitute or head coach may request a head coach’s conference with the referee if the coach believes a rule has been enforced improperly. If the rule enforcement is not changed, the coach’s team will be charged a timeout, or a delay penalty if all timeouts have been used.
1. Only the referee may stop the clock for a head coach’s conference.
2. A request for a head coach’s conference or video review must be made before the ball is snapped or free-kicked for the next play and before the end of the second or fourth period (Rule 5-2-9).
3. After a head coach’s conference or video review, the full team timeout is granted if charged by the referee.

Article 5 - Injury Timeout

a. In the event of an injured player(s):
1. An official will declare a timeout and the player(s) must leave the game. He must remain out of the game for at least one down, even if his team is granted a team timeout. When in question, officials will take a timeout for an injured player.
2. The player(s) may not return to the game until he receives approval of medical personnel designated by his team.
3. Officials, coaches and trainers shall give special attention to players who exhibit signs of a concussion. (See Appendix C.)
4. Whenever a participant (player or game official) is bleeding, has blood saturated on the uniform, or has blood on exposed skin, the player or game official shall go to the team area and be given appropriate medical treatment. He may not return to the game without approval of medical personnel. (A.R. 3-3-5:I-VII)
b. To curtail a possible time-gaining advantage by feigning injuries, attention is directed to the strongly worded statement in "The Football Code" (Coaching Ethics).
c. An injury timeout may follow a charged team timeout.
d. The referee will declare a timeout for an injured official.
e. Following a timeout for an injured player of the defensive team, the play clock shall be set at 40 seconds.
f. Ten-Second Runoff. If the player injury is the only reason for stopping the clock (other than his or a teammate’s helmet coming off, (Rule 3-3-9) with less than one minute in the half, the opponent has the option of a 10-second runoff.
1. The play clock will be set at 40 seconds for an injury to a player of the defensive team and at 25 seconds for an injury to a player of the offensive team (Rule 3-2-4-c-4).
2. Rule 3-4-5 applies. (A.R. 3-3-5:VIII and IX)

Article 6 - Violation Timeouts

Article 7 - Length of Timeouts

a. A charged full team timeout requested by any player or head coach shall be one minute plus the five-second referee notification and the 25-second play clock interval. (Exception: Rule 3-3-4-e-3).
b. Other timeouts shall be not longer than the referee deems necessary to fulfill the purpose for which they are declared, including a radio or TV timeout, but any timeout may be extended by the referee for the benefit of an injured player (Refer to Appendix A for the guidelines for game officials to use during a serious on-field player injury).
c. If the team charged with a full team timeout wishes to resume play before the expiration of one minute and its opponent indicates readiness, the referee will declare the ball ready for play.
d. The length of a referee’s timeout depends on the circumstances of each timeout.
e. Penalty options must be exercised before a team timeout.
f. The intermission after a safety, try or successful field goal shall be not more than one minute. It may be extended for radio or television.

Article 8 - Referee’s Notification

During a full team timeout (Rule 3-3-7-a) the referee shall notify both teams after one minute. Five seconds later he shall declare the ball ready for play.
a. When a third timeout is charged to a team in either half, the referee shall notify the field captain and head coach of that team.
b. Unless a visual game clock is the official timepiece, the referee also shall inform each field captain and head coach when two minutes or less of playing time remain in each half. He may order the clock stopped for that purpose. If the game clock is running at 2:00 and the ball is dead, the clock shall be stopped and the two-minute warning given then. If the ball is live at 2:00, the two-minute warning shall be given after the ball becomes dead.
1. The play clock may be interrupted for this purpose and shall then be reset to 25 seconds.
2. The clock starts on the snap after the two-minute notification.
3. Competitions may adopt regulations that even if a visual game clock is the official timepiece, a two-minute warning shall still be given.
c. If a visual game clock is not the official timing device during the last two minutes of each half, the referee or his representative shall notify each captain and head coach of the time remaining each time the clock is stopped by rule. Also, a representative may leave the team area along the limit line to relay timing information under these conditions.

Article 9 - Helmet Comes Off — Timeout

a. If a player’s helmet comes completely off through play, other than as the direct result of a foul by an opponent, the player must leave the game for the next down. The game clock will stop at the end of the down. The player may remain in the game if his team is granted a charged timeout.
b. When the helmet coming off is the only reason for stopping the clock, other than due to an injury to the player or his teammate (Rule 3-3-5), the following conditions apply (A.R. 3-3-9:I-III):
1. The play clock will be set at 25 seconds if the player is on offense and at 40 seconds if the player is on defense. With one minute or more remaining in either half, the game clock will start on the referee’s signal.
2. Ten-Second Runoff. If there is less than one minute in the half the opponent has the option of a 10-second runoff, unless the helmet comes off as the direct result of a foul by the opponent. Rule 3-4-5 applies.
c. If the ball carrier’s helmet comes off as in paragraph a (above) the ball is dead (Rule 4-1-3-q). If the player is not the ball carrier the ball remains alive, but he must not
continue to participate in the play beyond the immediate action in which he is engaged. Prolonged participation is a personal foul (Rule 9-1-17). By definition such a player is obviously out of the play (Rule 9-1-12-b).

SECTION 4. Delays/Clock Tactics

Article 1 - Delaying the Start of a Half

a. Each team shall have its players on the field for the opening play at the scheduled time for the beginning of each half. When both teams refuse to enter the field first for the start of either half, the home team must be the first to enter.
PENALTY − 15 yards from the succeeding spot [S21: DSH].
b. The home management is responsible for clearing the field of play and end zones at the beginning of each half so the periods may start at the scheduled time. Bands, speeches, presentations, homecoming and similar activities are under the jurisdiction of home management and a prompt start of each half is mandatory.
PENALTY − 10 yards from the succeeding spot [S21: DSH].
(Exception: The referee may waive the penalty for circumstances beyond the control of the home management.)

Article 2 - Illegal Delay of the Game

a. The officials shall make the ball ready for play consistently throughout the game. The play clock will start its count-down from either 40 seconds or 25 seconds, by rule depending on circumstances. A foul for illegal delay occurs if the play clock is at :00 before the ball is put in play (Rule 3-2-4).
b. Illegal delay also includes:
1. Deliberately advancing the ball after it is dead.
2. When a team has expended its three timeouts and commits a Rule 1-4-5-c-2 or 3-3-4-e infraction.
3. When a team is not ready to play after an intermission between periods, after a score, after a radio/television/team timeout, or any time the referee orders the ball put in play. (A.R. 3-4-2:I)
4. Defensive verbal tactics that disconcert offensive signals (Rule 7-1-5-a-5).
5. Defensive actions designed to cause a false start (Rule 7-1-5-a-4).
6. Putting the ball in play before it is ready for play (Rule 4-1-4).
7. Sideline interference (Rule 9-2-5).
8. Action clearly designed to delay the officials from making the ball ready for play. (A.R. 3-4-2:II)
PENALTY − Dead-ball foul. Five yards from the succeeding spot [S7 and S21: DOG/DOD].

Article 3 - Unfair Clock Tactics

Article 4 - 10- second Runoff from Game Clock — Foul

a. With the game clock running and less than one minute remaining in either half, before a change of team possession if either team commits a foul that causes the clock to stop immediately, the referee will subtract 10 seconds from the game clock at the option of the offended team. The fouls that fall into this category include but are not limited to:
1. Any foul that prevents the snap (e.g. false start, encroachment, defensive offside by contact in the neutral zone, etc.); (A.R. 3-4-4:III)
2. Intentional grounding to stop the clock;
3. Incomplete illegal forward pass;
4. Backward pass thrown out of bounds to stop the clock;
5. Any other foul committed with the intent of stopping the clock.
The offended team may accept the yardage penalty and decline the 10-second runoff. If the yardage penalty is declined, the 10-second runoff is declined by rule.
b. 10-second runoff procedures are specified in Rule 3-4-5.

Article 5 - 10-second Runoff from Game Clock — Common Procedures

a. The 10-second rule only applies if the game clock is running when the event occurs and the event causes the game clock to stop.
b. If there is a 10-second runoff, the game clock will start on the referee’s signal. If there is no 10-second runoff, the game clock will start on the snap.
NOTE: This rule supersedes Rule 3-3-2-f (snap supersedes referee’s signal) but does not supersede Rule 3-3-2-g (running clock). (A.R. 3-3-2:VIII and IX)
c. If the team that caused the event has a team timeout remaining they may avoid the
10-second runoff by using a team timeout. In this case the game clock will start on the snap after the timeout.
d. The 10-second runoff does not apply when both teams are equally responsible for stopping the clock (e.g. offsetting fouls, or injured or helmet-off players from both teams). (A.R. 3-4-4:IV)

SECTION 5. Substitutions

Article 1 - Substitution Procedures

Article 2 - Legal Substitutions

A legal substitute may replace a player or fill a player vacancy provided none of the following restrictions are violated:
a. No incoming substitute shall enter the field of play or an end zone while the ball is in play.
b. No player, in excess of 11, shall leave the field of play or an end zone while the ball is in play. (A.R. 3-5-2:I)
PENALTY − [a-b] Live-ball foul. Five yards from the previous spot [S22: SUB].
c. 1. An incoming legal substitute must enter the field of play directly from his team area, and a substitute, player or departing player must depart at the sideline nearest his team area and proceed to his team area.
2. A departing player must immediately leave the field of play, including the end zones. A departing player who leaves the huddle or his position within three seconds, after a substitute becomes a player, is considered to have left immediately.
d. Substitutes who become players (Rule 2-27-9) must remain in the game for at least one play and replaced players must remain out of the game for at least one play, except during the interval between periods, after a score, or when a timeout is charged to a team or to the referee with the exception of a live ball out of bounds or an incomplete forward pass (A.R. 3-5-2:III and VII)
PENALTY − [c-d] Dead-ball foul. Five yards from the succeeding spot [S22: SUB].
e. When Team A sends in its substitutes, the officials will not allow the ball to be snapped until Team B has been given an opportunity to substitute. While in the process of substitution or simulated substitution, Team A is prohibited from rushing quickly to the line of scrimmage with the obvious attempt of creating a defensive disadvantage. If the ball is ready for play, the game officials will not permit the ball to be snapped until Team B has placed substitutes in position and replaced players have left the field of play. Team B must react promptly with its substitutes.
PENALTY − [e] (First offence) Dead-ball foul. Delay of game on Team B for not completing its substitutions promptly, or delay of game on Team A for causing the play clock to expire. Five yards from the succeeding spot [S21: SUB]. The referee will then notify the head coach that any further use of this tactic will result in an unsportsmanlike conduct foul.
(Second or more offence) Dead-ball foul, team unsportsmanlike conduct. An official will sound his whistle immediately. 15 yards from the succeeding spot. [S27: UC- UNS].

Article 3 - More than eleven players on the field

a. Team A may not break the huddle with more than 11 players nor keep more than 11 players in the huddle or in a formation for more than three seconds.
Officials shall stop the action whether or not the ball has been snapped.
b. Team B is allowed to briefly retain more than 11 players on the field to anticipate the offensive formation, but it may not have more than 11 players in its formation if the snap is imminent. Whether the snap is imminent or has just occurred, the officials shall stop the action. (A.R. 3-5-3:IV)
PENALTY − [a-b] Dead-ball foul. Five yards at the succeeding spot. [S22: SUB]
c. If the officials do not detect the excessive number of players until during the down or after the down is over, or if Team B players have entered the field just before the snap but have not been in the formation, the infraction is treated as a live-ball foul. (A.R. 3-5-3:V-VI)
PENALTY − Live-ball foul. Five yards at the previous spot. [S22: SUB]