I've see that called both ways - sometimes allowed and sometimes not.
He was covered up to start the play - appeared to step back slightly as 80 went in motion to that same side.
Hard to tell without looking down the line at how the others were lined up to see if he was back far enough.
There has to be a certain number of players on the line - even if he steps back if that results with not enough players on the line - it is still a penalty unless they include the player in the count.
Bottom line if a formation is close to being illegal just don't run it to avoid the chance.
The gators have some issues on one side of their defense. All the big UM runs so far have come to that same side. The UM OL just buried them both times.