Legal or not?

[Suudy]

Originally Posted by cmathews

Granted I don't have my books with me. However, I don't recall any language in the rulebook that says that A must be a potential blocker before B can push them out of the way to get the ball.

It does, in rule 9.2.3d:

Art. 3...A defensive player shall not:
d. Contact an eligible receiver who is no longer a potential blocker.

Coupled with 2.3.5b (emphasis mine):

Art. 5...A defensive player may also:
b. Push, pull or ward off an opponent in an actual attempt to get at the runner or a loose ball if such contact is not pass interference, a personal foul or illegal use of the hands.

In the original post, it can be argued that A2 is no longer a potential blocker, thus the contact, even if in an attempt to get to the QB, is illegal use of the hands.

I think the question is whether A2 (or any other eligible receiver) is a potential blocker when behind the line. The key, I think, in the original post is that "A2 is looking back to the QB", thus is no longer a potential blocker.