Not a huge deal with his contract. Had they kept Pierce and KG they would have had to pay pierce a shitload this year and KG a shitload over the next 2. At least they get some picks in return for those 2.
Now instead of having PP and KG and finishing with 45 wins or whatever and getting bounced in the playoffs they more than likely finish close to the lottery.
All In all they have stockpiled 4 picks they didn't have by unloading Rivers, KG and Pierce. I know picks aint worth as much if they are out of lottery and more than likely all 4 of these picks will be in the 20s but still gives them a shot to package them or strike gold with one of them.
At the same time if they suck or rondo is out longer they will be in the lottery this year which gives them a higher pick.
They still can also move rondo or green if they find the right deals. Green will have max floor time this year for the first time in his career and he has the potential to be VERY good.
One thing I always liked about Ainge is he is NEVER afraid to pull the trigger on a deal