The fact that this can't be the primary concern does not stop it from being a concern. If only from the opportunity cost of signing Teixeira vs. being able to blow the bank on Sabathia.
You can't have too much pitching. You can have too many corner infielders.
If you had the choice between Youk at 3B, Teixeira at 1B and Wakefield in the rotation, or Lowell at 3B, Youk at 1B, and Sabathia in the rotation, which do you think you'd go for?
I'd say it's obvious that you should go for Sabathia, not because either option is bad, but because Youk, Lowell and Sabathia is more likely to be a truly great combination than Youk, Teixeira, and Wakefield. And then if you're worried about 3B at the start of the year, you have Lowrie, Lugo, Youk, Bailey, and Carter on hand to mix and match until Mikey's ready, or you can sign Casey Blake to fill the role you were looking to crowd Mikey into.