All you have to do is pay attention to what Schaeffer is doing. Here is how it breaks down:
UT needs a starting quarterback and their options for next year are Schaeffer (if he stays), Clausen, Cropton and Ainge.
Schaeffer has demonstrated many inconsistencies towards the end of the season, having missed numerous classes and practices. You cannot have a starting player, much less a guy who's supposed to be a team leader, acting like this. Not to mention he will not be able to iron out his inconsistencies if he does not practice. He will not improve if he doesn't play.
Next up is Clausen. While Slick Rick has acted well enough as a patch due to the injuries of Ainge and Schaeffer, I'm afraid he does not have what it takes to lead a team like what needs to be done. It is too late in his college career to learn what he needs to in order to give UT any sort of effective passing. He will be a senior next year, and he simply does not have the experience to keep UT going for a full season. And yes, aside from one play, I appreciate everything he has done for us in stead of the Fab Freshmen.
Crompton is still all of what, 17? It should go without saying that starting a QB in his first year of a football program (when he's still 17 or 18, no less) is a flat-out bad idea. Let him watch, and learn the offense through what he sees. There can be exceptions, but as a general rule, starting true freshman qb's = bad idea. We got lucky with Ainge, don't expect lightning to strike twice.
Speaking of Ainge... That just leaves him. He's young, learning the program at a rapid rate, and has shown that with some improvement, he has the potential to be a leading QB in the SEC. Over the offseason training, I expect Sanders to do big things with Erik.
This all just my opinion... But I feel pretty well-justified in it.