Pass Interference is a penalty that occurs when one player impedes another player’s ability to do his job during a passing play. Usually this takes the form of pushing, grabbing, or blocking without looking for the ball. Pass interference can be called on the offense or the defense.
Offensive Pass Interference: Most frequently called when a receiver makes an obvious attempt to create space between himself and a defender, usually by shoving him out of the way. Offensive PI can also be called in a “pick play” scenario, when another offensive player intentionally runs down a defensive player in order for a teammate to get open. Penalty: 10 yards, replay down.
Defensive Pass Interference: Most frequently called when a defender illegally impedes a receiver’s ability to catch a pass – especially if he does so without looking behind him for the pass (telltale PI giveaway). Penalty: automatic first down at the spot of the foul (unless it occurs in the end zone, in which case it’s an automatic first down and the ball is placed at the 1-yard line).