I think it's possible that Sully could see that type of PT. I just don't know what Brad Stevens is going to do. Personally, I'm not that big on the idea that some people have that we play all the bigs like 20 minutes a game (that's roughly 96 minutes divided by 5 for Lee, Sully, Johnson, Olynyk, and Zeller).
Right this second, I'd put Zeller's butt on the bench, because I believe he has the least to offer in terms of upside and current talent. Some people dramatically say it's "not fair" to bench some of these guys. But to that I respond, it's not like Zeller is playing behind McHale, Parish, and Walton. If he can't play his way into a rotation of middle-of-the-pack players, he has no one to blame but himself.
So I wouldn't mind some sort of combination of Sully getting 28-30 mpg with Lee, Johnson, and Olynyk splitting the rest of it assuming Sully actually lives up to his potential.