ASHBURN, Va. -- Clinton Portis will be out at least a month with a groin injury, putting the two-time Pro Bowl running back's future in doubt once again.
His injury leaves the Washington Redskins with a very inexperienced backfield, too.
Coach Mike Shanahan said Wednesday that Portis has a third-degree separation of the left groin, with the muscle separated off the bone. Portis will not require surgery, and the coach estimated a recovery time of four to six weeks.
"That's disappointing," Shanahan said, "that working so hard, playing so well, that he's got that setback."
Portis was hurt in Sunday's 17-12 win over the Philadelphia Eagles, when he was already starting to share more of the rushing load with Ryan Torain. Now the only two healthy tailbacks on the roster are Torain and Chad Simpson, who have combined for 70 carries in their NFL careers heading into this week's game against the Green Bay Packers.
"Some guys have got to step up," Shanahan said. "Ryan has got a little playing time, and we'll see what he can do."
Portis has run for only 195 yards on 49 carries this season. He's 109 yards shy of 10,000 for his career and is 680 away from breaking John Riggins' franchise rushing record. Both milestones seemed inevitable a year ago, but Portis missed the last eight games of last season after a suffering a severe concussion during a helmet-to-helmet hit.
The Redskins brought in veterans Larry Johnson and Willie Parker to challenge Portis this season, but both were cut after Portis held them off for the starting job. Portis said he renewed his focus and dedication, something necessary for a well-worn 29-year-old back who would be expected to be in his declining years. But he's also in the final year of his contract and wouldn't appear to fit into the future of a team being remolded by Shanahan.
Shanahan will now do what he so often did when he was coach of the Denver Broncos: turn to a new face in the backfield to replace an established name. Backs were almost interchangeable for Shanahan's teams in Denver, from Terrell Davis to Reuben Droughns to Tatum Bell to Mike Anderson to Portis, because of a perennially solid offensive line.
Torain was drafted by Shanahan's Broncos in the fifth round in 2008, but Torain broke his left elbow in training camp and played in only two games before tearing the ACL in his left knee. He had another knee injury in training camp in 2009 and was released.
"Definitely got labeled that," Torain said. "I definitely felt like I had to get that bug off my shoulder and stay healthy. ... Luck wasn't on my side my rookie year."
Torain didn't make the Redskins at the start of this season and was placed on the practice squad. He was promoted two weeks ago and has rushed for 116 yards on 25 carries in two games, including a 12-yard touchdown against the Eagles in which he bowled over safety Quintin Mikell on the way to the end zone.
"I watch it anytime I get an opportunity," Torain said.
Torain will start against the Packers, and Shanahan said the team will almost certainly add a third running back to the roster before Sunday.
"Ryan has the ability to be a top back," Shanahan said, "and we'll find out in time if he can do that and stay healthy."
Meanwhile, the Redskins are changing punters. With Josh Bidwell still bothered by a hip injury, the Redskins have reached agreement with Hunter Smith, a league source tells ESPN NFL Insider Adam Schefter. Smith punted in 13 games for Washington last year.
Also, the Redskins signed running backs Javarris James and Keiland Williams to the practice squad and released linebacker Mike Balogun from the practice squad. Williams was waived from the 53-man roster on Saturday.
Information from The Associated Press was used in this report.