Tyler Polumbus and Maurice Hurt weren’t the highest-profile players on the roster when the Washington Redskins opened training camp last week. It appeared they would return to backup roles along the Redskins’ offensive line after being pressed into service as fill-in starters in the second half of last season.

But with the Redskins already missing two injured starters on their offensive line less than a week into camp, Polumbus and Hurt could have great significance in determining the course of the Redskins’ season and the rookie-year success of quarterback Robert Griffin III.

The Redskins were awaiting word Tuesday on the extent of starting right tackle Jammal Brown’s hip injury. In the meantime, Polumbus continued to practice with the starting offense in Brown’s place. Hurt spent a second straight practice filling in at left guard for Kory Lichtensteiger, who underwent arthroscopic knee surgery Monday.

“If one guy goes down, somebody else jumps right in to take his place and tries to play at that same level,” Hurt said Tuesday.

Brown was examined Tuesday by a specialist in New York. Coach Mike Shanahan said at Redskins Park that he had no immediate updates on Brown’s status. Brown, who has been on the training-camp version of the physically unable to perform list since aggravating his hip injury running sprints last week before camp began, said he had not yet received test results.

“I’ve been real down about this,” Brown said in a telephone interview. “I worked so hard this whole offseason, only for this to happen. It’s hard. I’m trying to stay positive and just wait for things to play out with all the medical procedures.”

Polumbus made four starts last season in his first year with the Redskins. Prior to that, he’d totaled 15 starts in four seasons with the Denver Broncos and Seattle Seahawks.

“I have no idea what’s going on with injuries,” Polumbus said. “I have no idea when Jammal is going to be back. My job is to step in and make sure there’s no loss of production and show that there is a lot of depth on this team.”

The team signed veteran offensive tackle Jordan Black on Monday. Black, 32, has made 40 starts in eight NFL seasons for the Kansas City Chiefs, Houston Texans and Jacksonville Jaguars. But only 11 of those have been since the 2006 season, and Black did not play in the NFL last season. Black is unable to practice for a few days because of rules in the sport’s collective bargaining agreement.

“My expectation is to expect nothing, hope for nothing, just to compete,” Black said after participating in the Redskins’ morning walk-through in their indoor practice facility at Redskins Park.

Shanahan played down the possibility of the Redskins acquiring a veteran free agent who might be capable of stepping in as an immediate starter.

Hurt made eight starts last season after the Redskins had selected him in the seventh round of the 2011 NFL draft out of Florida.

“I prepare like I’m going to be there, until I’m not there any more,” Hurt said. “That’s the name of the game. . . . Kory is a great player. I’m sure he’s going to be back. But until he gets back, I’ll hold it down for him.”

Shanahan said Monday that he hopes Lichtensteiger will return to the lineup for the Sept. 9 regular season opener at New Orleans. For now, the Redskins are left testing the depth of their offensive line.

The Redskins did little on the free agent market in the offseason to upgrade their offensive line. That perhaps was a result of the $18 million salary cap reduction imposed on them by the league just before free agency began. The Redskins still made significant moves at wide receiver, but plans they apparently had to sign an offensive lineman or two apparently were scrapped.

The NFL, with the consent of the players’ union, reduced the Redskins’ salary cap by $36 million over two years as a penalty for the way the team loaded player salaries into the 2010 year, when there was no salary cap.

So the Redskins arrived at training camp last week with their offensive line unchanged from last season. They had to hope that left tackle Trent Williams would make a successful return from his four-game suspension, that Lichtensteiger would come back from surgery for two torn ligaments in his right knee and that Brown’s hip would hold up.

It’s been so far, so good with Williams. But Lichtensteiger underwent surgery after doctors determined that particles in the guard’s knee cartilage needed to be “cleaned up.”

Shanahan said Lichtensteiger could recover in time to play in the third of four preseason games. But the Redskins will take no such risk with him, Shanahan said, and will target his return for the regular season opener.

Mike Jones contributed to this report.