The only logic I can ascribe to it, and it's terribly flawed I know, is that he's failed totally to illicit any interest as a heel so they're going to try him as a face to see if they can get at least two people to give a shit about him.
That or Vince popped a fucking boner over the idea of A-Train vs Morgan and A-Train vs Big Show.
Edited to add : If A-Train went back to his old look of pants and a black T, I'd have a little more time for him, the hairy-back gimmick is fucking appalling.