I don't think it would work all that well.
(1) Too limited defensively to guard quick forwards. Transition defense, stopping dribble penetration and closing out on shooters would all take a hit.
(2) His perimeter game would be defended against much more effectively by quicker opponents so his post game would become his main weapon. In that case, Boston would need two jump-shooting bigs to space the floor out enough to run him down low often enough to take advantage of that post game. Difficult to piece together.
I imagine it would look a lot like Pierce + J.Green together on the wings, lots of iso and post offense with limited ball and player movement that is far too easy to defend against.
I could see it as an option now and then but I think his main positions will be at PF and C.