I think Sato and Thad are probably borderline starters/6-7th men on most playoff teams. This makes them somewhat overpaid, but in specific context of the Bulls, they're pretty far down the list of concerns. I'd happily trade them, but I don't imagine there'd be any takers.
If I were running the Bulls, I'd look at it like this:
* I'm looking to trade Lauri now, while it's conceivable that a team will offer up a lottery pick for him. Time to shuffle that deck.
* Because of that, I see value in keeping Thad as a placeholder capable player.
* Sato's value is that he can capably play 1-3. Especially 3. He's legitimately a 3 in size in today's league, and is fine, perhaps even better playing there. That's our weakest position, and to put it charitably, Sato is a flat out better player than Chandler Crutchison.
So as I look to build the team for next year, what I see is 6 guys in our rotation, and I want to add two draft picks and because we're currently a trash team, we're going to pencil them in to the rotation at whatever their position is. That gives us an 8 man rotation already.
3- Porter, Sato
4/5- Carter, Young
+ Our own draft pick
+ Draft pick from trading Lauri
Filling out the bottom of the team is not something I'd want to invest much money on. Our second rounder usually makes the team, so that only leaves 5 more spots.
Felicio, Kornet, Arci, Crutch, and Gafford are already under contract.
Now, in the abstract, I'd be fine with cutting Arci and/or Felicio to bring back Shaq and/or Denzel, or signing someone completely different. But I'd also admit that we're talking about the Bulls here, and we're talking about the end of the roster, so it's just as likely we keep those guys around. Especially given the current financial climate where Reinsdorf and everyone else is losing money. In that situation, eating Arci's contract to pay another $1.5M to bring back Shaq or Val (or a FA from another team) seems kind of unlikely.