Steelers safety Troy Polamalu could miss Sunday's game against the Dolphins. Polamalu, out for the last six games and most of a seventh with a left knee injury, only began running on Monday. He has yet to begun cutting, turning or twisting, moves needed to play in a game. "[Monday] was a positive step," coach Mike Tomlin said. "The door's not closed on him participating. ... He's just progressing, trying to get him ready, hopefully to play."