I think he'd be a good fit here because of the way he plays. KG, Sheed, and Baby are all outside big men that can stretch the floor, while Perk plays close to the basket. Now if you match everybody up it seems like, at times, we'll have nobody down low to crash the boards and score inside... Big Ben could do that for us.
Plus a 4 time AS and 4 time Defensive player of the year, even at 35, could be very useful as your 4th big.