When the offense runs a pass play from scrimmage and the pass falls incomplete the game clock immediately stops. This incomplete pass can be a bad pass, blown route, batted away ball or a ball thrown out of bounds for lack of options. When the offense wishes to stop the clock intentionally, the same rule applies to a spiked ball immediately following the snap. The quarterback receives the snap and immediately throws the ball into the ground in front of him. This spike is considered an incomplete pass according to the game clock rules.
Out Of Bounds
Anytime a player in possession of the ball goes out of bounds the play clock stops. According to the NFL Rule Book, the clock is re-started once the officials spot the ball at the appropriate yard line on the field except during the last two minutes of the first half or the last five minutes of the fourth quarter. During these times the clock doesn’t start again until the next snap. The offense must run the play before the play clock runs to zero, however.
If a player in possession of the ball has his forward progress stopped in bounds and is then pushed out of bounds, the officials may mark the player down in bounds at the point of forward progress and signal for the clock to continue running.
Change Of Possession
When a change of possession occurs during an NFL game, there is a stoppage in play to bring the proper offensive and defensive units onto the field. This change of possession is typically following a fumble recovery, interception, kickoff or punt.
When the game officials call a penalty on either team, the clock stops until the penalty yardage is sorted out and the ball is spotted at the appropriate yard line.
When a team scores a touchdown or kicks a field goal, the clock stops immediately until the extra point or ensuing kickoff takes place.
The purpose of a time out is for a team to organize its game plan while the game is not in progress. As the name “time out” indicates, the clock stops when a team calls for one.
The game officials can elect to stop the clock at any time to allow medical personnel to tend to player injuries. This stoppage is usually reserved for times when a player cannot get off the field on his own in a quick manner.
Play Clock Reset
Since 2005 the NFL requires the play clock to be reset to 10 seconds if the game is stopped with less than 10 seconds remaining. Before this rule change, the play clock was reset to 25 seconds. This rule is meant to keep teams from facing a severe disadvantage when clock stoppage happens that is no fault of their own.