Russell Martin sure would be nice to have right now.
I've heard Ivan Rodriguez's name floating around, which seems like a pretty bad idea since he's going to give you the same offensive production as Salty at the very best, and he's old as f***. I'm not sure where his defense is right now, but it can't be where it once was.
Bengie Molina played for both World Series teams last year, so with him the Sox are basically a lock. I'd go for it.