Vierling, Rogers, Ibanez, Mize, Vest and Brieske. That's more than half the roster with the guys you mentioned. Of course some of the answers weren't good. Wentz gone. Miller and Maeda can't be counted on.
The rookies have a lot to prove but have played well. There's depth available in the minors still.
Maybe the biggest question of all, Chris Fetter is the real deal. He's capable of getting the best performance out of the pitching staff and that's a big advantage going forward.