In gridiron football, ineligible receiver downfield is a penalty that is called when a forward pass is thrown and an ineligible receiver is beyond the line of scrimmage without blocking an opponent at the time of the pass. An exception is on screen plays where the ineligible player is allowed to cross the line of scrimmage to go out and block because the ball is still being caught behind the line of scrimmage. This exception, however, does not apply to the NFL. A member of the offensive team considered an eligible receiver by the rules of the game, in most leagues, are the running backs, wide receivers, and tight ends. Ineligible receivers include the center, offensive guards, and offensive tackles.