No. It simply isn't. He may not be... but that evidence is still to be had.
Yeah. You could say that but it is nothing like an "excuse for poor performance". It is allowing the poor performance to occur before punishing someone for it. It is called using intelligence rather than emotional whim to determine whether someone can or cannot perform.
I have seen practice info like this come out on QB's not just with the Vols but elsewhere. Guys in the NFL who go on to have great seasons passing often struggle in pre-seasons games as they work on something that is not a strength.
These "struggles" could be that he is truly neck and neck with these other guys. OR it could be that he has already proven he can do things that they are working on and has moved on to something more challenging.
Without knowing what you do, I would venture that I have fired more people for performance than you have. I have quantified problems, explained the standard, then held them to it. NO EXCUSES.