It wasn't me!
Ya gotta be preemptive with this kind of stuff in the preseason. Write down rules about this sort of thing beforehand so when it comes up there's nothing anyone can dispute.
I personally don't see any reason why you can't refund him his money and lock his team.
Grady Sizemore will have more value than Jason Bay regardless of draft position
Aramis Ramirez in 155 G will hit over .300 40 HR 110 RBIs
Brian McCann will have more value than Jorge Posada regardless of draft position