I agree with those who say Montero stays in the minors.
As stated here, many think Montero won't stick as catcher. But it seems that the Yankees are so in love with the idea of Montero's production in the catcher spot (once Posada retires) that they want to give him every chance to improve defensively.
If he doesn't totally suck as a catcher, then I wouldn't be shocked to see 3 catchers on the club next year. Montero/Posada/Cervelli split catching duties while Montero/Posada split DH duties. (which is why Nick Johnson got a one year deal to be DH) This isn't your normal problem carring three catchers, since two of them are real hitters. (If Cervelli still has options next year, they might use him shuttling between the majors and AAA)
Then they see if Montero sucks as a big league catcher with him only catching 40-50 games.
I just don't think they want Montero branded a DH when he is so young.
Obviously, this is pure speculation on my part based on being a die hard Yankee fan who tries to read between the lines when Cashman and others speak. (Note: Cashman is an expert at talking for a half hour and saying nothing of substance!)
There are a few things with the New York Yankees that never change. That's pride, tradition, and most of all, we have the greatest fans in the world. -Derek Jeter, 9/21/08 -- last words from old Yankee Stadium