If the words uttered by his backups are any indication, Redskins fans need not worry.
Shaun Alexander, Ladell Betts, Rock Cartwright and Mike Sellers all touted their credentials as quality fill-ins should Portis' sprained left knee keep the NFL's second-leading rusher out of a game that will be pivotal for Washington's playoff chances.
"At the end of the day, if Clinton can't go," Alexander said, "I'll be ready."
Trying to keep a gauge on it all was coach Jim Zorn, who is making contingencies based on balky knees. Portis sprained an MCL in the loss to the Pittsburgh Steelers before the bye, and Betts was limited in Wednesday's practice while attempting to return from a more severe left knee sprain that has caused him to miss three games.
"If Clinton can't go, it's going to be a community position," Zorn said. "If Ladell is near 100 percent, I would feature Ladell. If Ladell's not 100 percent, I think I would feature Shaun Alexander -- and then Rock Cartwright would be a bigger factor as well."
Portis, whose 995 yards includes 121 in the Week 4 victory over Dallas, would have to get much better in a hurry. He's already been ruled out for Thursday's practice and there's concern whether his knee will again swell up and whether he can regain any kind of burst by Sunday.
"He could straighten out his leg, so we were hip, hip hooraying," Zorn said. "He's working hard to get back. It just remains to be seen whether he can or not."
Never fear. The calvary is ready for a game the Redskins (6-3) need to stay ahead of the archrival Cowboys (5-4).
Start with Betts, who had a 1,154-yard season two years ago when Portis missed eight games with injuries. Betts had 156 yards on 38 carries in six games this season before getting hurt.
"It's nothing new for me. I've had to do it before," Betts said. "This is my seventh year in the league, and Shaun's been in the league a long time and played at a high level, and Rock's been here, so it's nothing new for us."
Alexander, meanwhile, says he has his slow start with the Redskins figured out. At issue is whether the 31-year-old former MVP, back in the league after injuries prompted the Seattle Seahawks to cut him, still has anything left in the tank -- or whether he simply needed time to adjust to his new teammates.
"It's kind of weird," Alexander said. "I feel like I've just gone through a preseason, and now here's the regular season about to start. I'd always play a little bit in the first game, a little bit more in the second game, hardly none in the third and nothing in the fourth. And so I finally am comfortable with the offense and the line."
Sure enough, that's been his pattern over four weeks since joining the Redskins: three carries for 8 yards, six carries for 11 yards, one carry for 4 yards and a bye week.
"He's improving," Zorn said. "He's really understanding the way we play is a little different than what we had him do in Seattle."
Then there's Cartwright, who has been itching to get the ball on offense -- something that has happened only five times this season and sporadically in his seven-year career.
"I'm all for it," he said. "If my opportunity arises, I'm going to do my best to take advantage of it."
What none of those three can do is block as well as Portis, which could be a factor in keeping quarterback Jason Campbell away from the Cowboys pass rush.
"He'd be a real loss because of his blocking skills and his meanness," Zorn said. "He can get after it. That is a key issue for me."
The forgotten man of the bunch is Sellers, who has been used this season almost exclusively as a blocking fullback.
"You guys should bombard the head coach with that," Sellers said. "Let him know that Sellers has been known to run the ball a little bit."
When Sellers' lobbying was mentioned to Zorn, the coach gave a short response that won't give his big back much hope.
"OK," Zorn said. "I appreciate that."
Notes: WR Santana Moss (hamstring) practiced and seems set to play Sunday. ... CB Shawn Springs (calf) is expected to practice Thursday but is also expected to play. ... The team is less optimistic about LB Marcus Washington (shoulder) and DT Anthony Montgomery (Achilles).