I like TJ and have defended him (somewhat unsuccessfully) last year. He got the dogsnot beaten out of him and kept coming back and tried to make plays. Re-watch those three losses, especially Penn State, and you will see the entire Defense just pouring past our Oline and blasting him repeatedly. Tom Brady couldn't function well under those conditions (See the SB when his undefeated team faced the Giants, pressure screwed him up).
Having said that, AC is the better QB. No doubt. But I'm thrilled to have TJ as the backup, he's very good.