I like Jason Collins coming in to defend Hibbert.
Hibbert isn't much of an offensive threat against guys with legitimate size but he can destroy an undersized power forwards if they are on him. I don't think either Sully or Bass are capable of defending Hibbert.
So Collins is needed for a few minutes tonight while KG is resting + while Hibbert remains on the floor. When Mahinmi comes on, Doc can use Sully at center.