 unless he is within one yard of the line of scrimmage (as opposed to in American football).Any player may block another player's passage, so long as he does not hold or trip the player he intends to block.The kicker may not be contacted after the kick but before his kicking leg returns to the ground (this rule is not enforced upon a player who has blocked a kick), and the quarterback, having already thrown the ball, may not be hit or tackled.