ASHBURN, Va. — Washington Redskins coach Jim Zorn says running back Clinton Portis is “very, very doubtful” to play against the Denver Broncos on Sunday because of a concussion.

Portis was knocked out of last weekend’s 31-17 loss to the Atlanta Falcons.
Zorn met with Washington’s leading rusher at the team’s practice facility Wednesday and said Portis “needs to get rest.”
He said Portis went to see a doctor for tests. Portis did not speak to reporters.
In other Redskins injury news, strong safety Chris Horton had toe surgery Wednesday and was put on injured reserve, ending his season. Horton was hurt against Atlanta.
Washington filled Horton’s roster spot by re-signing running back Quinton Ganther, who was released last week.