Tyler Polumbus and Maurice Hurt weren’t exactly 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 suddenly, there is every reason to closely scrutinize all of their practice-field maneuvers. With the Redskins already minus two injured starters on their offensive line less than a week into training camp, the performances of Polumbus and Hurt could be significant in determining the course of the Redskins’ season and the rookie-year success of quarterback Robert Griffin III.  

Polumbus has been practicing with the starting offense at right tackle with Jammal Brown on the training camp version of the physically unable to perform list because of his ailing hip. Hurt and rookie Josh LeRibeus have taken turns filling in at left guard in place of Kory Lichtensteiger, who underwent arthroscopic knee surgery Monday.

   The Redskins hope to know more soon about Brown’s status. He is scheduled to be examined by a doctor Tuesday, according to the team. Coach Mike Shanahan said Monday he’s hopeful that Lichtensteiger will be able to return to the lineup for the Sept. 9 regular season opener at New Orleans.

   In the meantime, the Redskins are left testing the depth of their offensive line, with Shanahan saying Monday he’s confident in the players now filling in.

   “We do have some depth, which is nice,” Shanahan said. “So if you do lose one or two guys, you’re expecting some guys to come in and fill the void…. At least you have some people in there that can compete. So that’s a big plus.”

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

   Shanahan played down the possibility of the Redskins making further moves in search of a veteran free agent who might be capable of stepping in as an immediate, clear-cut starter.

   “Those guys aren’t out there,” Shanahan said. “If they were out there and we thought somebody was better than the people we had, we would have tried to get those players.”

   The Redskins did little on the free agent market in the offseason to upgrade their offensive line. That perhaps was a product 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 the plans they’d apparently had to sign an offensive lineman or two seemingly were scrapped. The NFL, with the consent of the players’ union, reduced the Redskins’ salary cap by $36 million over two years for the way the team structured players’ contracts during the sport’s season without a salary cap in 2010.

   So the Redskins arrived at training camp last week with last season’s offensive line unchanged. They had to hope that left tackle Trent Williams would make a successful return from his four-game suspension at the end of last season for violating the sport’s substance-abuse policy, that Lichtensteiger would come back from his knee injury last season and that Brown’s hip would hold up.

   It’s been so far, so good with Williams, and some team officials are convinced he will have a superb season. But Brown’s hip, which has plagued him in recent seasons, began bothering him again while he was running sprints before the opening of training camp, according to Shanahan. It’s unclear when he’ll be able to play.

   Lichtensteiger participated in the first two practices of camp last week. He was given what was termed a routine day off Saturday, and Sunday was a scheduled day off for all players. But Shanahan announced Monday that Lichtensteiger had undergone 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 the four preseason games. But the Redskins will take no such risk with him, Shanahan said, and will target the regular season opener.

   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.

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

   Some eyebrows were raised when the Redskins chose LeRibeus in the third round of this year’s draft out of Southern Methodist. Some draft analysts had projected him as a lower-round pick. But the Redskins could end up relying on him sooner than expected. He worked at center during offseason practices, and was a left guard with the first-team offense Saturday. Hurt took over Monday at that spot.

   One thing the Redskins have going for them is that the offensive line could be aided by the mobility of Griffin, which has been on full display during training camp. Griffin said Monday he trusts the offensive line that’s now in front of him.