A 12-man pitching staff (presumably) leaves three players for the bench. Francisco Cervelli looks like a lock to open the year as Jorge Posada's backup. Ramiro Pena is the pre-spring training favorite for utility infielder, but prospects Reegie Corona, Kevin Russo and Eduardo Nunez may have something to say about that. This leaves the third spot available to an outfield/DH type.
Since there are so many players still on the market who fit the bill, it's almost impossible to tell who will be the guy. Below are some potential options.
UPDATE: There's two open spots, not one, taking into account a DH, a backup catcher and infielder.
Within the organization:
Most talked about:
Jerry Hairston jr.
If it were my choice, I'd go with Hairston. I like the way he plays and his versatility.