I don't think I would consider Mize a core piece, but at this point can be serviceable enough to ride out his control. Honestly, I was just hoping he could bang out innings at a league average performance this season. I was ready for a rougher first half in terms of pulling back the pitching while maybe stamina affects him in the second half. The jury is still out, but if he ends up solid middle of the rotation, I think that's fine at this point. I wouldn't worried about 1/1 status at this point.
If only Manning could find enough game to get there. We can still foolishly hope he's just successfully working on stuff that isn't evident in the stats, can't we?