Trade him for Monroe . Start Monroe at Center ..Zeller backup
Keep KO at PF .
Then Monroe leaves next year and you gave up Sully for nothing.
Monroe has a trade clause. So he could actually pick were he would want to go and resign. Green is friends with him, and they share the same agent. DA did right by Green when Green agreed to waive his contract when he went down with the heart issue, and the next season DA gave him a nice contract. Which will sit well with Green and his agent, which in return help talk up the Celtics to Monroe.
YEah he can still bolt, but so could Sully after a couple more seasons. There are no guarantees, but I have huge faith in the organization and how well players receive the franchise once they get hear. Plus how good would it be if they can bring KG in for one more season as a player/big man coach and maybe get Monroe to play some legit D.
So I say roll the dice. Sully isn't really lighting it up, KO has been out playing him the last few games, even on the D, which is saying some thing.
Also the Celts should still be bad enough they could get an other PF if they feel Monroe wont resign. Kinda the nice thing about the butt load of picks DA gathered.