<Li> A forward pass is ruled incomplete . (Included in this is the rule whereby the quarterback can "spike" the ball near himself without being called for intentional grounding .) </Li> <Li> Either team calls for a timeout or an official calls for a timeout, perhaps because a player is injured or there is a penalty on the play . Officials will restart the clock after an official timeout, but not a team timeout, has concluded unless another of the conditions applies, or if the timeout is for a penalty enforcement after the 2 - minute warning of the first half or inside the last 5 minutes of the second half (absent special timing rules for a specific foul). <Ul> <Li> 10 seconds will be taken off the clock, and the clock started when the ball is spotted, if the offense, after the 2 - minute warning of either half, fouls or commits certain other acts that cause the clock to stop (including an injury when the offense is out of timeouts, except under certain circumstances), unless the clock will stop anyway for a different reason . </Li> </Ul> </Li> <Ul> <Li> 10 seconds will be taken off the clock, and the clock started when the ball is spotted, if the offense, after the 2 - minute warning of either half, fouls or commits certain other acts that cause the clock to stop (including an injury when the offense is out of timeouts, except under certain circumstances), unless the clock will stop anyway for a different reason . </Li> </Ul> <Li> 10 seconds will be taken off the clock, and the clock started when the ball is spotted, if the offense, after the 2 - minute warning of either half, fouls or commits certain other acts that cause the clock to stop (including an injury when the offense is out of timeouts, except under certain circumstances), unless the clock will stop anyway for a different reason . </Li>

When does the clock stop in nfl football