Realistically, if he cuts it as a 5/8 it's pretty handy value for a spine player, and if he bombs and does have to go back to the Centres then it makes him probably the most highly paid Centre getting around, but he also has potential to be one of the best Centres getting around, so even if he's a little overpaid in that role, it's hardly a complete disaster.
Personally, I'm a little more risk averse and wouldn't have wanted to commit 5/8 money to him until I knew he could play the role, but I still don't see keeping him on the money being discussed as being an awful piece of business either way.