You're not sure why that would have anything to do with SS? SS is a MI position. A MI, by definition, has to be able to play SS. True-but to get a backup MI, all they need is somebody who can play 2nd or SS, as long as they are confident that the other 3 can all play both SS and 2nd. There will never be a situation where they will absolutely have to have that other backup play SS, so there's no reason why the backup would have to play SS. That would be preferable, but not a real deterrent if they find a good backup who only plays 2B. Izturis is coming back from injury so the Cubs may want a defensive insurance policy for SS. This would allow both DeRosa and Theriot to play in the same game while keeping Izturis (or his would be substitute) in the game for defensive purposes. Well if Izturis got hurt during a game that both DeRosa and Theriot was playing, then whichever one was playing 2nd could switch over to SS and the backup come in to play 2B. It would be great if we could get a guy who could cover both positions, but I would rather just get the BPA who could play at least one of those 2 positions. Yes, but I think the bottom line message here is that Lou isnt comfortable with the defense that DeRosa or Theriot provide at SS. In an emergency, one or the other could play SS but if Izturis goes down for an extended period, the Cubs probably want a skilled defensive specialist to step in and play.