Rule 2 – Section 18 – Article 2 – Offside on a scrimmage play

After the ball is ready for play, offside occurs (Rule 7-1-5) when a defensive player:
a. Is in or beyond the neutral zone when the ball is legally snapped; or
b. Contacts an opponent beyond the neutral zone before the ball is snapped; or
c. Contacts the ball before it is snapped; or
d. Threatens an offensive lineman, causing an immediate reaction, before the ball is snapped (Rule 7-1-2-b-3-Exception, (A.R. 7-1-3:V Note)); or
e. Crosses the neutral zone and charges toward a Team A back (A.R. 7-1-5:III).

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Rule 7 – Section 1 – Article 2 – Shift and False Start

b. False Start. Each of the following is a false start by Team A if it occurs prior to the snap after the ball is ready for play and all players are in scrimmage formation:

3. A restricted lineman (Rule 2-27-4) moving his hand(s) or making any quick movement.
   Exceptions:
   (a) It is not a false start if a Team A lineman immediately reacts when threatened by a Team B player in the neutral zone (Rule 7-1-5-a-2) (A.R. 7-1-3:V)
   (b) It is not a false start if the snapper takes his hand(s) off the ball, provided this does not simulate the start of a play (Rule 7-1-3-a-3).