NFL rule changes for 2010 A defenseless player cannot be hit in the head or neck by an opponent who launches himself and uses his helmet, shoulder or forearm to make contact. Previously, this applied only to receivers.
When a ballcarrier loses his helmet, the whistle will blow and the ball will be placed at the spot where the player lost it.
The umpire will be stationed behind the offensive backfield rather than in the linebackers area.
During a field goal or extra point, no player can line up directly across from the snapper. Previously, a player needed to have his helmet outside the snapper's shoulder pads.
A dead ball personal foul on the final play of the second or fourth quarters will cause a 15-yard penalty on the second-half or overtime kickoff. Previously, no penalty was enforced.
If a punt returner makes a fair catch signal and muffs the ball, he is entitled to a "reasonable opportunity" to catch the muff before it hits the ground without interference of the coverage team. In case of a penalty, the ball will be placed at the spot of the interference but no yardage marked off.
When a ball strikes a videoboard (as one punt did last preseason at Cowboys Stadium), guide wire or sky cam, the play is whistled dead and replayed. The game clock is reset to when the play started.
If the clock is stopped in the final minute of either half for a replay review but would not have stopped without the review, officials will run off 10 seconds before resuming play. Either team can take a timeout to avoid the runoff.