Redskins' running back Clinton Portis is expected to miss the team's game against the Cowboys on Sunday with a left knee sprain. "He's continuing to get treatment," Coach Jim Zorn said Thursday. "I was hoping today there would be a little more optimism, and there's not. There was no change. I was looking for another jump, but there wasn't." Ladell Betts is also hurting, meaning that Shaun Alexander could get a majority of the carries against Dallas.