People keep trying to move puzzle pieces around to form a traditional line up with a 4 and 5, but that's not Brad Stevens. He doesn't want that. The Celtics have had ample opportunity in Stevens time here to go after a big man, they don't. The one move for a big they made was Al, and he was hardly a traditional big. He was a 4 who played 5, but didn't have the traditional game of either. He was a good defensive player one on one, but not a rim protector, not a rebounder, and he rarely posted up.
My guess is give Stevens and Ainge another good asset - like say the Memphis pick turns gold 18 months from now - and I'd wager that unless there's a superstar talent like James Wiseman there - Ainge will take the best guard or wing available.
They draft guards and wings, and take spare parts for bigs. It's pretty obvious that they don't prioritize bigs, and I don't expect that to change as long as CBS is our coach. Can't recall who, but some of you have said "it's a big man's game." Nope. It's a perimeter man's game. Look who wins titles, GSW, Lebron and Kyrie, Kawhi in Toronto and SA. You want a title, you have to be elite on the perimeter.