NFL Video Rulebook

Rule Summary View Official Rule

An official shall declare the ball dead and the down ended:

1. when a runner is contacted by an opponent and touches the ground with any part of his body other than his hands or feet. The ball is dead the instant the runner touches the ground. A runner touching the ground with his hands or feet while in the grasp of an opponent may continue to advance; or
   
   

   Note: If, after contact by an opponent, any part of a runner’s leg above the ankle or any part of his arm above the wrist touches the ground, the runner is down.

2. when a runner is held or otherwise restrained so that his forward progress ends.
3. when a quarterback immediately drops to his knee (or simulates dropping to his knee) behind the line of scrimmage.
   
   

   Note: If a quarterback does not immediately drop to a knee, and contact from a rushing defender is unavoidable, it is not a foul unless the defender commits some other act that would constitute unnecessary roughness.

4. when a runner declares himself down by:
   1. falling to the ground, or kneeling, and clearly making no immediate effort to advance.
   2. sliding feet-first on the ground. When a runner slides feet-first, the ball is dead the instant he touches the ground with anything other than his hands or his feet.

   Notes:

   1. Defenders are required to treat a sliding runner as they would a runner who is down by contact.
   2. A defender must pull up when a runner begins a feet-first slide. This does not mean that all contact by a defender is illegal. If a defender has already committed himself, and the contact is unavoidable, it is not a foul unless the defender makes forcible contact into the head or neck area of the runner with the helmet, shoulder, or forearm, or commits some other act that is unnecessary roughness.
   3. A runner who desires to take advantage of this protection is responsible for starting his slide before contact by a defensive player is imminent; if he does not, and waits until the last moment to begin his slide, he puts himself in jeopardy of being contacted.
5. when a runner is out of bounds.
6. when an opponent takes a ball that is in the possession of a runner who is on the ground.