We're going to find a closer.
Personally I think Hansen is up for the job. So far we have seen 2 seasons of Hansen without his slider, which was an absolutely natural, ball-buster throughout his college years. You can watch his video from St. Johns on the 2005 MLB Draft Tracker and see his slider behaving naughtily.
Hansen has not found that in the bigs yet, and has so far lacked the ability to get ahead enough to make that pitch effective. I see no reason to believe that between Okajima, Hansen, Timlin, Delcarmen, Tavarez, Pineiro, Donnelly and Romero there is not someone who can be MLB average closer. Beyond that I think that Edgar Martinez, Bryce Cox, Justin Masterson (who is being groomed as a starter, isn't he?) and Daniel Bard can do it next year (or this year if they're phenomenal). Finally, Wakefield has closed in the past and Jon Papelbon is always an emergency option.
Closers are overrated unless you can get one who is absolutely dominant (Mariano, K-Rod, etc.,) then they will put your team over the top. Given that that guy doesn't appear available, MLB average to start out with would be great.