It'd take a helluva haul to take him...but, I mean...if the doors were blown away for Castro...or anyone for that matter, you can't keep him just b/c he's yours if it helps the team succeed.
Exactly what is the right price? If I am offered King Felix for him I would take it, but I doubt you would say that is realistic. Without a baseline deal for Castro then it is hard to answer yes or no.
I'm gonna say no because I don't think anything I would take for him would realistically happen. Castro seems like a sure thing and I don't wanna give that up for 2 unlikelys, a maybe, and a probably.
If the price is right, deal. What's the right price? I'd say a proven veteran who is still in his prime and consistently produces in the field and at the plate.