Being able to make a basic pre-snap read is pretty fundamental at the SEC level though, and he can't do it.
The thing that sucks for JG is that I wonder if his growth/progression are permanently stunted because of his experience at Tennessee. We know he didn't get great coaching under the Butch regime, and since Butch left he's seen 2 more OCs. There's little doubt Chaney knows what he's doing, but remember he said he was "throwing everything" at JG this offseason. The dude just has to be totally overwhelmed by his time here; he's seen 4 different offensive styles with different verbiages, etc. Chaney in particular is probably asking him to do some advanced (for him) things.
He's got to play better, but it also is little wonder why he plays like he has no idea what he's doing. He can't be a leader, because he doesn't know what he's doing himself.