penalty
 

A 2/9 at A-41. Normal pro set for A, TE is off theline on the left side. At the snap, TE moves down field. The LB on that side, had moved to abut 3 yards off the LOS before the snap) shoves him out of the way and the TD falls down (about 2 steps off the LOS). THE QB throwing a quick pass towards where the TE should be, pass falls incomplete. A's coach calling for DPI. Thoughts??

Can't have DPI before the ball is in the air. Could have illegal use of the hands if the TE is no longer a potential blocker.

Correct. DPI is only while the ball is in the air. Illegal use of hands and holding can happen any time. However in this situation it sounds to me like the LB hit the TE as they were passing each other and so it doesn't sound to me like there was any foul. 2 steps from the LOS hasn't allowed the TE to establish himself as not a blocker.

NCAA
Is there something in the rulebook about a reciever 'Establishing as a (non-)blocker'?
I don't remember anything, but have heard from people that NFL has some sort of 5 yard rule for bumping a reciever.
As far as I understand a CB can bump a receiver whenever, as long as the ball is not in the air and the block is legal (no PF, not in the back etc).

I see all the time that the CB is 7-10 yards back and the receiver runs downfield. Could be for a pass route, could be to block the CB. As long as the ball is not thrown I don't see a problem with a bump - but I'm usually an U so maybe I'm not well versed enough on the topic.

James

NCAA rules allow B to block (or legally contact) an A eligible receiver until A is at a position relative to B where he would no longer be considered a threat to block. In practice, until A is on the same yardline or beyond B, and the ball is not in the air, B can block A. Also, there is no "five yard" limit on where B can block.

Provided that the block described here did not qualify as some form of "contact foul", the block by B is not a foul under NCAA rules.