Since the 2016 season In the
National Football League (NFL), a chop block is an illegal move, penalized by a 15-yard loss. If the foul is committed by an offensive player in their own end zone, the penalty automatically results in a
safety. Before the 2016 NFL owners meeting, chop blocks were legal under certain circumstances. It was considered legal on running plays when (i) the blockers were aligned next to each other on the
line of scrimmage, (ii) the blockers were lined up anywhere on the line and the flow of the play is towards the block or (iii) the cut blocker was aligned in the backfield and the chop block took place outside the original
tight end position. The cut blocker is said to "chop" the defender and usually engages simultaneously with or immediately after the high block. A "reverse chop" occurs when the high block comes immediately after the low block and the same rules apply. ==NCAA==