If Sullinger can play defense at a high level, he will get minutes.
We haven't seen him defend in the Cetltics' scheme, or against NBA talent.
So, at this point we know nothing about whether he will play at all, much less get substantial minutes.
But where?
It's easy to make these sweeping general statements. But where is he going to play?
At the 4? Maybe eventually. I like him better than Bass in some ways. However, the Celtics didn't just give Bass and Green a combined 15 million dollars per year to sit on the bench. And there aren't enough minutes at the 3 for Green to get all his minutes there.
At the 5? People seem to think he can play there, and maybe he can a bit. But I think this is notion is somewhat based on a distortion of the past, where people remember BBD playing the "5". However, BBD played next to KG when he did this. So the idea that Sullinger can backup KG is fairly far-fetched, as it would require the C's to go very small with essentially two undersized power forwards manning the 4/5 spots.
If Sullinger is to have a chance to contribute in his rookie year, I think he's going to have to hit the ground running early. I think that one of the ways that the C's will make up for Avery Bradley's absence will be to slide PP to the 2 for 5-10 minutes a game, which should free up enough minutes for Green to get nearly all his minutes at the 3 spot. If that's the case, there should be minutes for Sullinger.
If he shows he can do what Bass can do or more, I think the C's may try to move Bass around the deadline. But if not, I think Sullinger gets his butt parked on the bench for most of the games once the team is fully healthy.