One of Brad/KT will be gone, I absolutely expect that. We'll be getting a defensive big to replace whoever goes. There are a whole group of bigs that can be had for Brad or KT and would be bring what we need in the front-court in solidity or quality. It's unlikely we get KG or Ben Wallace, but there are still starting bigs out there who can be had and would fit into what we want for our FC. In free-agency, value of Nene/Pryzbilla/Nazr is likely too much for us.
Then, get a back-up center in FA or the draft, since we don't have one right now. Potapenko is not a certainity and isn't going to be relevant to our main FC. Right now, he's still the back-up center, but who honestly sees him staying around as that? At best on this team he'll be a third C, it's either that, or he's out.
Brad Miller/Kenny Thomas/Shareef/Potapenko - average, and obviously not planned, like that because of trades not purposed for the FC.