You are thinking about this the wrong way. Who exactly is going to match up on Shaq? The bulls have no one who can be physical in the key. Noah will get abused. Shaq may have some issues on the pick and roll, so I guess if the Bulls can consistently hit mid range jumpers they can stay in a game
But the Cavs don't have any problems scoring on the Bulls anyways, they proved this the game they recently played them without LeBron.
Shaq will slow down the overall pace of the offense and hurt them on defense. Individually he will be effective, but I think he'll hurt the overall team game against the Bulls. Will it matter in the end? Probably not, but I do think it could make the series take one game longer than it should have.