Here's the general advice I have been giving people:
He probably won't regain MVP status (I think he has peaked already), but it would be foolish to sell so low on him right now.
If you get a nice offer, by all means, trade him. But don't trade him for the "sake" of it, or because some other GM has been bugging you for a few months to do it (the wear down tactic is a dangerous one).