NFL Video Rulebook Play Clock
Rule 4 Section 6
Rule 4 Section 6
The play clock is set to 40 seconds immediately after a play ends (unless it follows one of these scenarios). If the ball is not snapped before the play clock expires, it is a delay of game.
The play clock is set to 25 seconds after certain administrative stoppages, including:
The Referee can reset the play clock to 25 seconds by pumping one hand vertically.
When there is a 10-second runoff, the clock starts on the referee’s signal. A 10-second runoff occurs when a team commits any of these acts after the two-minute warning with the clock running:
There is a 10-second runoff if a replay review of a play after the two-minute warning results in the on-field ruling being reversed and the correct ruling would not have stopped the clock.
This runoff only applies to the offense. The defense always has the option to decline the 10-second runoff and have the yardage penalty enforced, but if the yardage penalty is declined, the 10-second runoff is also declined.