From the official:

General manager Brian Cashman has made it clear that pitching prospect Philip Hughes is as close to untouchable as any player in the Yankees' farm system.

But what about Melky Cabrera?

According to a Major League executive, the Yankees and Pirates have discussed a deal that would send the young outfielder to Pittsburgh in exchange for outfielder Jeromy Burnitz and first baseman/outfielder Craig Wilson.

I'd have to give that one a pass.