What it is

Several offensive players change positions before the snap and do not all come to a stop, set, for a full second before the ball is snapped.

The penalty

The penalty is 5 yards, and the down is replayed. The penalty is enforced from the line of scrimmage.

More detail

Officials throw a yellow flag when they see it. The other team may accept the penalty or decline it if the play turned out better for them.

Animated play

Blue circles are the team with the ball. X marks the other team. The yellow oval is the ball.

1. When several offensive players change positions, they must all stop and be set for one full second before the ball is snapped.
2. Here the group is still on the move when the ball is snapped.
3. The official throws a flag. It is a five-yard penalty and the down is replayed.