If Celtics decide to take a flier on Larry Sanders, instead of cutting a young kid with no trade value, Ainge should send Zeller, Amir and Terry Rozier to the Bulls in exchange of Rajon Rondo and Taj Gibson. Maybe Chicago would agree to send a future pick for taking Rondo out of their franchise and sending a promising prospect in Rozier, but the point is Gibson would replace Amir and Larry Sanders would take Zeller's spot.
http://www.espn.com/nba/tradeMachine?tradeId=jrulgeoCeltics would improve their rotation and roster:
IT/Rondo/DJ
Bradley/Smart/Green
Crowder/Brown/Young
Gibson/KO/Jerebko
Horford/Sanders/Mickey
This team, if everything clicked the right way, would be better than the Raptors/Hawks and put a fight against the Cavs. Of course, big ifs are is Rondo able to play a similar role to last year's Evan Turner and will Larry Sanders be able to play at all. IMO Taj Gibson would be a great fit with Al Horford.
Losing Rozier sucks, but, barring a blockbuster trade, Ainge will need to decide what to do with IT/Smart/Bradley in the guard department, and by retaining BKN pick and cap flexibility he would have a lot of options.