Oddly, I could see it. Seattle has a long history of signing old players to cheap one year deals in the past. It adds to the competition. Wagner would be a stud at WILL. It's a very weak LB class and I think Seattle probably wants to wait til next year before spending a good pick on one, so signing Urlacher as a 1 year stopgap makes sense. He also comes from a similar defense and could mentor the young LBs we have.
Obviously, Urlacher isn't what he once was, but the Seahawks know that. Pete got some very nice results out of a 36 year old Lawyer Milloy in 2010. Not saying it should happen or will happen, but if it did I'd "get it."