Taylor was never the most athletic OL. Then he compounded that with a poor performance against Clemson (to be fair, he was playing against a couple of first-class DLs that night, and got no help from his RT Jackson).
Still, I'm guessing what got him deep in the doghouse was not so much the performance against Clemson, but his response to a sub-par outing on the national stage. He gained flabby weight, despite having world-class nutrition available to him at a cost of $0. On top of the weight issue, he was otherwise out of shape. Then he compounded all of that with a DUI.
He has a loooonnnnggg way to go to prove he's reliable in the clutch. I hate it, but it really is self-inflicted.