Donovan McNabb's status unknown

ASHBURN, Va. -- It could be a smoke screen or just a cautious assessment of his quarterback's health, but Mike Shanahan says he's not certain Donovan McNabb will be available for the Washington Redskins' season opener against the Dallas Cowboys.

"I really don't know for sure," Shanahan said Sunday. "That's why it's day by day. We'll see how it goes."

McNabb hasn't practiced since spraining his left ankle in the second preseason game against Baltimore. He sat out Friday's game against the New York Jets and watched Sunday's practice with a black sleeve on his left leg.

Shanahan said the leg is too sore for McNabb to play Thursday against the Arizona Cardinals, but McNabb likely wouldn't have played in that game anyway because the coach prefers to rest his starters and some of his top backups in the final exhibition to avoid injuries. No. 2 quarterback Rex Grossman said he won't play this week either, leaving John Beck and Richard Bartel to take the snaps against the Cardinals.

The news from Shanahan was more positive concerning running back Clinton Portis, who sprained his right ankle against the Jets.

"I don't think it's too serious. It's not a big setback," Shanahan said. "I would anticipate him being able to practice in a couple of days."

Fullback Mike Sellers, who missed the Jets game, remains day to day with a sprained left knee. Backup linebacker Perry Riley sprained his right ankle against New York and was wearing a walking boot Sunday.

After pulling his left hamstring working out with McNabb in Arizona the week before training camp, Malcolm Kelly was on the filed for Sunday's light practice and plans to play in the preseason finale.

Kelly missed the first three preseason games and has fallen behind other receivers as the Redskins look ahead to the final roster cuts on Saturday. The third-year receiver was a second-round selection in 2008, but he knows some people are wondering if he'll turn out to be another wasted draft pick.

Information from The Associated Press contributed to this story.