I'm not buying the Poeltl talks unless the Cs are not committed to Rob as the long term 5. Maybe we see a Poeltl trade (and long term contract) and Rob is moved in the off-season but I really doubt it.
To me the two more likely scenarios are
The Cs use one of their TPE and lesser assets (2nd rd picks maybe Yam?) to acquire a stop gap big who can come off the bench and eat minutes when AL or Rob miss time. EX A Drummond from the Bulls, W Hernangomez from Pelicans, M Muscala from Thunder, T Lyles from Kings, R Lopez from Cavs
The Cs make a real asset costing trade (move Pritchard, future picks and probably Galo) for a 4/5 type big to be the eventual replacement for AL in the rotation. This player will have to have enough perimeter skill to play along side Rob. I would assume that the traded for play Rob and Grant will form the 3 man 4/5 rotation of the future for the Cs. EX Naz Reid from Minn, KO from Jazz, Zach Collins from Spurs , Tillman from Memphis.