The legal clipping zone for interior offensive linemen has been modified. It disallows any offensive lineman more than one position away from the defensive lineman to clip legally within the three-yard scrimmage zone. Purpose: to protect defensive linemen, who will know from where the potential legal clips might come.

Offensive players can legally block with extended hands anywhere on the field. Previously, only offensive linemen could block with extended arms in the scrimmage zone. Purpose: a safer way to block, most feel, than below-the-waist.

Chop-blocking is illegal. The NFL has long preached to its coaches not to teach this potentially dangerous blocking technique to its offensive linemen. The chop block, which usually occurs on sweep plays or pass plays, occurs when a defensive player is blocked high by one offensive player while a second offensive player blocks him in his knee or thigh area. Now, the offense will be penalized 15 yards for setting up a defensive player with a chop block. Purpose: to minimize the potential for leg injuries suffered by defensive players.

Players can't block below the waist after a change of possession play. A 15-yard penalty will be assessed to offenders. Purpose: bodies fly on kickoffs and punts with players knocking into the legs and shoulders of opposing blockers; this will increase safety on such plays.

On fake punts, defensive backs will have more freedom to jam potential receivers. Previously, defensive players could "chuck" receivers within five yards of the line of scrimmage. On fake punts, however, defensive players did not have an adequate chance to stop receivers. Purpose: erase an inequality on such plays.

Clarified the intentional grounding rule by noting that a quarterback can legally stop the clock to save playing time by throwing the ball forward towards the sideline.

Tightened the roughing-the-passer rule. Before, pass rushers were allowed to take two steps and hit the passer after the ball had been thrown. Now, after the passer's throwing motion has been completed, the pass rusher may take one step toward the passer and make full contact. After the first step, though, the pass rusher must show he is trying to avoid contact. Any aggressive action at this point will result in a 15-yard penalty against the defense. Purpose: to protect passers.