This creates a hole in the rules that Cincinnati and Tampa Bay have been victims of this year; the QB leaves the pocket, and then one of Team A's recievers is blocked out of bounds (in a block that would ordinarily draw a flag for illegal contact), he returns immediately, and subsequently catches an apparent TD pass. Trouble is, since the QB left the pocket prior to the contact, that block isn't an illegal contact foul, so the reciever who was blocked out of bounds can't get his eligiblity back unless someone else touches the pass before it gets to him.
