What it is

The offense does not snap the ball before the play clock runs out.

The penalty

The penalty is 5 yards, and the down is replayed. The play clock is 40 seconds after the previous play ends, and 25 seconds after some stoppages such as a timeout. If it reaches zero before the snap, an official throws a flag and the ball is moved back five yards from the line of scrimmage.

More detail

Teams often burn a timeout to avoid it, which is why you see a quarterback frantically signaling to the sideline. On fourth down near the line to gain, those five yards can turn a planned go-for-it into a punt or a field goal.

Animated play

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

1. The offense gets to the line and the play clock starts counting down.
2. The quarterback stalls, or the offense is slow to get set, and the clock reaches zero before the snap.
3. The officials throw a flag. The ball moves back five yards and the same down is played again.