The neutral before the snap is the width of the ball, and only the ball and the center's hands may be in the neutral zone. At the snap, the neutral zone is extended downfield by the length of a player's arm.
Defensive players may contact offensive players with hands (chucking receivers; fending off potential run-block) but cannot cross through the neutral zone (with their feet) and move into the backfield unless:
- After a four Mississippi count
- A blitz has been called
- A fumble
- The QB no longer has ball in hand
- Offensive players are blocking with feet into or past the neutral zone
Likewise, offensive players can make contact with defenders in the neutral zone with hands, but cannot maintain contact with their feet in or past the neutral zone on a forward pass, before another player has touched the ball. Ineligibles cannot move past the neutral zone on a forward pass until the ball (or punt) has crossed over the neutral zone.
Note, there is no pass interference for passes that do not cross past the neutral zone, offensive or defensive, or for deflected balls.
If a forward pass is thrown across the neutral zone, offensives can actively chuck defenses across the neutral zone and then block in their own backfield, but may not block a defender with feet in or past the neutral zone.
If a backward pass, handoff or other running play, the offense can immediately contact defenders and block them downfield, while defenders can actively shed blocks and cross into the neutral zone if the offensive linemen step into or through the neutral zone.
Last updated: Jan.29.2018