Dejuan Blair is a good comparison in my opinion. Sullinger has better range.
Actually upon further thought this is the best comparison
Jared Sullinger = glen Davis.
You are comparing a top 10 lottery pick to two 2nd rounders.
Also, Glen Davis never had a back to the basket game. He has always been a face up 4 who is extremely overweight. Sullinger is a bit overweight (but has shown the ability to lose it year to year), but his weight problem is nearly on Davis's level.