The Washington Post reports Redskins RB Clinton Portis, who left Sunday's game at Atlanta with a concussion, was "knocked out," according to coach Jim Zorn. Zorn said it was too early to say how long Portis might be out, if at all. "He had kind of one of those smiles on his face that you know [he] was wondering what the heck happened," Zorn said. "I would never make a diagnosis on a guy getting knocked out. We just have to wait and see. There'll be some tests to see whether or not there was a concussion and how long it takes." Zorn said the team would be "cautious" about Portis's return, leaving his status for Week 10 against Denver in question.