The Dolphins have signed quarterback J.P. Losman, replacing Sage Rosenfels as their backup to Matt Moore. A blood disorder sent Rosenfels to the hospital in August, and he said in a statement that he hasn't fully recovered. "When I first joined the Dolphins, all tests showed that I was healthy and ready to go," Rosenfels said. "But after practicing for a few weeks, especially in the heat, some new indications made it obvious that I need to rest and allow my body to regain all requisite strength."