The tuck rule was a controversial rule in American football used by the National Football League from 1999 until 2013. It stated:
NFL Rule 3, Section 22, Article 2, Note 2. When [an offensive] player is holding the ball to pass it forward, any intentional forward movement of his arm starts a forward pass, even if the player loses possession of the ball as he is attempting to tuck it back toward his body. Also, if the player has tucked the ball into his body and then loses possession, it is a fumble.[1]
This is referred to as the tuck rule because the ball leaving the quarterback's hands is considered a forward pass even if the quarterback intends not to pass the ball, but instead continues the forward motion to tuck the ball back into his body. Only once the forward motion of the arm is completed, and the ball tucked into the quarterback's body, would a subsequent loss of possession be considered a fumble.
Mike Pereira, the former director of officiating of the NFL, noted that the design of the rule avoids the question of the quarterback's intention,[1] except that the referee still must judge whether the initial forward movement of the arm was "intentional".