Oak has a many major league ready players Garcia (whatever his name is now), Cruz, Barton, etc. but no place for them, maybe Garcia. That sounds like wasted depth, though I have no idea what the eventual Zito trade will entail.
If Chavvy needs to DH or sit, Perez will take his spot at 3rd. Thomas will never once play the field for any reason. He's far too fragile to risk on defense. Johnson will be the 1B, although Swisher may play a few games there. The two guys most out of playing time are going to be Payton and Kielty, but unfortunetly both of them hit better against lefties, so there isn't an obvious platoon.