Criscito is more effective as a SW/CB, Grygera is the likely RB, but I see your point. I was just trying to illustrate that a redundant player for 5m would be money better spent than on this guy for 10 even. I would also argue that Cris wouldn't be better than the CBs we have, since Criscito, Grygera and Chiellini all can play CB and would do so better than Cris would.
Personally, I think some combination of Barzagli and a proven CB would be ideal. Someone like Cannavaro, Marquez, Milito, Mexes, Chivu, etc.