It's an interesting point.
Though I think I saw somewhere we can easily create over $25M in cap room next year by getting Harvin and Cassel off the books, cutting McKelvin, and a couple other things like that. Plus we still have restructures for Mario and Clay in our back pocket, and of course the cap will jump.
That extra 4 mil seems paltry in comparison to having one reliable, steady quarterback on the roster this season, in my opinion.