Sullinger is an excellent positional rebounder with great rebounding fundamentals. Regardless of athleticism he will be a high volume rebound player.
He also has great instincts as a back to the basket post player with enough lower body strength and size to get the position he needs to be effective scoring underneath. He has a very sweet, turning, right handed baby hook and the strength to create space and get off his shot.
Like Baby, he's a below the basket player with slightly below average height but Sully has longer arms and reach and is definitely a better mid range shooter from when Baby enter the league. Scola, Davis, Humphries, Brand, Hayes, Blair are all guys that have similar size and skill sets and athleticism and been highly successful.
I don't think Sully will be an All-Star but he definitely could be a high quality starter in this league some day.