I don't know why I keep replying to you, because you repeatedly show some crazy moon 'understanding' of the game that makes me want to slam my head against the wall. But you realize that Shaq rebounds at a worse rate than Marion and does it for MORE money? Furthermore Shaq can cover ONE position on the floor, Marion can cover four. Shaq is a slug, he can't move horizontally at all, any guy with speed and good body control (i.e. Parker, Giniobili, Kobe, the guys the Suns need to stop) will go right around him.
The Suns are fine in the shot blocking department, they need good fundamental defense, good positioning, and good rebounding, Shaq offers approximately zero of them.