Wave off a penalty

[Wisdomofone]

I hate to complain about our yellow flag carrying fellows ..... so I will frame this in the context of a question.
I watched a sixman game Friday night and saw something happen that I did not completely understand. In this particular instance it was 4th down team A ran a sweep play. A player from team A was away from the ball and had clearly given up on the play. A player from team B hit him in the back (hard enough to knock him off his feet). The back judge threw a flag. I think his call was a personal foul. The coach from team B stormed on to the field screamed at the official and for some reason the white hat waved off the penalty. As far as I know there was no explanation given to team A coaching staff.

Is it legal to hit someone in the back after they have clearly given up on the play if you are on defense?

 

[loveofgame]

This is something that's really hard to judge without actually viewing the play. However, I'll answer as though your statement is completely true. No, you can't block in the back at anytime. Just because a player "quits" on a play doesn't alone make them unable to be blocked, just not in the back.

 

[ZeroRisk]

In that situation, you likely have one of three penalties.

1. Block in the back.

2. "Defenseless" player.

3. Unnecessary roughness.

Keep in mind that I wasn't at that game or part of the crew, so I'm just speculating, but if the coach was arguing, the call was likely "illegal block in the back" rather than the other two and the coach successfully argued that the player and block were too far away from the action to matter one way or the other and the officials thus waved the flag off.

If the call had been for 2 or 3, it doesn't really matter where the ball is and, in fact, strengthens the call that the player who was hit was obviously out of the play. 2 or 3 would have been thrown for am emphasis on safety and I don't see a wave-off in that situation.