Ineligible man downfield is a penalty called against the offensive team in gridiron football when a forward pass is thrown while a player who is ineligible to receive a pass is beyond the line of scrimmage without blocking an opponent at the time of the pass. A player is determined ineligible based on his position at the time of the snap. When the ball is snapped, the offense is required to have no more than eleven players on the field, out of whom only six are eligible. Offensive linemen, including the center, offensive guards, and offensive tackles, are generally ineligible receivers, while eligible receivers include the quarterback, running backs, fullbacks, tight ends, and wide receivers. However, the rule varies among leagues. For example, in the National Football League (NFL), a quarterback is an ineligible receiver if he is directly under the center when he receives the snap. The NCAA allows ineligible receivers to be a maximum of 3 yards beyond the line of scrimmage before the pass is thrown. The penalty for ineligible man downfield is 5 yards in both the NFL and NCAA. The purpose of this rule is to maintain game balance and make it easier on the defense. If offensive linemen were allowed downfield on a pass play, it would make it a lot more difficult for the defense.