There has been no word on what the Celtics received for Baynes. My guess is he was part of the trade where the Celtics traded #24 to the Suns for the garbage Bucks pick next year they owned. Doubtful the Celtics receive anything back for Baynes, since the Suns were earlier in the day clearing cap space.
So… Celtics trade #20 to the Sixers for #24 and #33, then trade #24 and Aron Baynes to the Suns for the Bucks’ 2020 first-round pick (top-7 protected, then unprotected in 2021). Their max cap room now increases to $34.8M.