Was he ever unavailable?
Moreover, who is likely to trade for him?
I think the only thing he'd be good for is if somebody has a multi-year veteran contract they're trying to unload to create relief moving forward.
Example: if Memphis wanted to trade Zach Randolph.
But Ainge probably wants to hold onto cap space on the off chance the Celts swing a big trade or get lucky in the lottery and become attractive to one of the more interesting free agents.