They need to draft or sign a decent young center, whether its one who is already somewhat proven or is very rusty and needs to be molded (kinda like in the case of Perk).
If we REALLY want to build for the future, then unfortunately they almost need to hope KG retires and they must must MUST trade Ray Allen at the trading deadline.
I'm ok with letting Pierce stay and retire a celtic.
If the Celtics sign Green longterm (which isn't even a guarantee anyway), he's going to have to start. He's just not the same player coming off of a bench, whether it be that he starts once Pierce retires or plays the 2 once Ray Allen is traded.
I'm ok with Rondo staying...I understand he's wildly inconsistent and this season has shown that he still has a long way to go in terms of being a top pg in the nba, but he's at least established, he's still one of the top defending guards in the league, so unless you can get a trade for Chris Paul, I say hang onto Rondo.
So to wrap up, I say keep Rondo, Pierce, Jeff Green, trade Ray Allen at the deadline, also hang onto Delonte, try and find a replacement for Davis but if you can't find anything, sign him back, and then look for bigs that aren't injury proned and ready to retire