I think Lee/Amir should be our starting frontcourt. When Lee's on the court, you have to feed him the ball at least 15% of your possessions or the fact that he can't do much without the ball will hurt you.
Hey good, he'll fit in with the rest of the team perfectly then with not being able to do much

Outside of Thomas, the C's Usage rate seems to be pretty uniformly distributed, so Lee can get the ball 20% of the time, and that's fine and fits in with the rest of the C's current style.
When Thomas is on the court, he needs to have the freedom to dominate the ball and attack double teams and individual defenders whenever he wants, which doesn't mesh with Lee (I'm assuming Thomas is coming off the bench).
Sure Thomas is best when he has the ball in his hands and can attack, but once teams adjust he's useless. What I saw watching the C's games, many times Thomas usually 1st off the bench and came in alone, and then about 2 minutes later others sub in. Thomas attacks for a couple of minutes, teams adjust, and you can throw in Lee giving you another offensive option.
Plus, while we all like to assume David Lee is going to play like he did in 2014, there's no guarantee he hasn't lost a step. He will be 32 after all, remember how good Troy Murphy looked in Indiana in '09, and remember how he played in Boston in '10? Very similar when you look at guys like Jermaine O'Neal and Michael Finley and Ray Allen (not-so subtle jab), how well they looked the year or two before they got to Boston, and then how we could see they clearly lost a step and weren't the same player any more once they got here.
I like Lee, hope he does well here, but I doubt Stevens is building the rotation around him. I still see Zeller as the starting C, Johnson as the starting PF. Lee, Olynyk, and Sullinger all battling for the minutes after that. But at the same time, we all know Stevens isn't scared to play around with the starters either, I'm sure we'll see a little bit of everything, but I don't see Zeller losing his starting spot (to start the season at least).