the Celts are going to lose Rozier. They can't sign him because he's proven to warrant starters money and starters minutes and they aren't trading Kyrie. So when do you trade him? this year, when his value is highest? Since when has Danny left valuable assets languishing while they lose value? Never. IT, Crowder, Zizic, Pierce, KG, etc. So the question is really how high can they move up in exchange for Rozier or Rozier plus other capital. The Celts are, potentially, one piece away and I think that piece is a rim protector who can shoot threes. I'd go all in on Bamba and his theoretically improved shot. He's bright as hell and would fit in with the culture here on the team and in the city, and he appears to be working hard refining his game (see the Ringer article). Defensively, imagine defending the three point line a year from now with a more mature Brown and a more mature Tatum along with Hayward, Horford, Morris, Semie while having a Bamba there to clean up mistakes. They could be very aggressive on the perimeter and still do a great job protecting the rim. In addition, he can guard the Celtics biggest threats in the East going forward, guys that we can't really guard now: Yannis and Embiid. If Bamba can refine his three point shot, then it's over on the offensive end as well given the talent that they can use to attack the rim after drawing the big away from the basket.
The Celts need to keep the Memphis pick and get a second rounder or two in return (cheap bench guys over the next couple years), but if Bamba falls to Orlando at six, then they should go Rozier, the Sacramento pick, #27, maybe the Clippers and next years pick for Bamba. By next year, anything short of taking down Golden State, given their remarkable progress, will be a disappointment.