Robert Griffin III is expected to give the Washington Redskins an infusion of life, but Coach Mike Shanahan continues to stress that the rookie quarterback’s success hinges largely on the play of his supporting cast.

The Redskins have upgraded at wide receiver. They boast two talented second-year running backs as well as a versatile veteran. But concerns remain about the offensive line, where two of the five starters are coming back from season-ending injuries.

The start of training camp has brought both good and bad news.

Starting left guard Kory Lichtensteiger, who tore both the anterior cruciate and medial collateral ligaments in his right knee last October and spent the last nine months rehabbing from surgery, practiced at full speed Friday and reported no setbacks

But starting right tackle Jammal Brown, whose surgically repaired right hip has landed him on injured reserve in each of the last two seasons, opened camp on the physically-unable-to-perform list after aggravating the injury.

When the offseason began in January, Shanahan put Brown on notice by publicly stating that the former Pro Bowl player needed a great offseason to save his spot on the team. Brown spent the winter and spring at Redskins Park and said a combination of yoga and treatment from the team’s athletic trainers had him feeling more flexible and mobile than he had in years.

But while running sprints during conditioning drills Wednesday, Brown hurt himself again. Shanahan said the team will not have an idea of how much time Brown will miss until an MRI exam is conducted Tuesday.

Despite the questions about Brown, the Redskins expect continuity to be one of their strengths. Left tackle Trent Williams is vowing to carry himself with maturity off the field and show Pro Bowl form on it. Lichtensteiger is saying, “I feel like my old self,” and center Will Montgomery and right guard Chris Chester are entering their second seasons as starters for Washington.

“I think it’s going to work wonders,” said Montgomery, who re-signed with Washington in February. “Another year in the league, another year together. I think we’re capable of some great things. We added some skill players, we’ll be able to run the ball a little bit, pass the ball a little bit. I think we should be in good shape.”

There is, however, the uncertainty created by Brown’s recurring injury.

“Yeah, it’s a concern,” Lichtensteiger said. “Jammal’s a great player and a leader on our team, especially our position group. I don’t know what’s going on with him, but hopefully he can get back. . . . But whoever steps up, we’re going to find a way to get it done, and I think we have enough quality backups and enough quality people in the room that we’re going to get it done.”

A lack of depth proved costly for the Redskins last year. Injuries to Lichtensteiger and Brown, coupled with the injury and suspension absences of Williams, forced the team to use eight offensive line combinations. At various points, three first-year players — tackle Willie Smith, guard Maurice Hurt and center Erik Cook — were pressed into duty and to no surprise they struggled.

Shanahan acknowledged after the season that insufficient depth hurt the Redskins. In April the team drafted guards Josh LeRibeus and Adam Gettis in the third and fifth rounds, respectively, and tackle Tom Compton in the sixth. LeRibeus has worked primarily at center this offseason while Gettis has taken snaps at both guard positions.

The team passed on signing any tackles with significant experience as insurance for Brown. That leaves Tyler Polumbus (who started four games at right tackle), Hurt (who started eight games at left guard), and Smith (who started three games at left tackle), to split time at right tackle. James Lee, a fifth-year tackle with 19 games under his belt, was signed as a free agent in the spring.

“We’ve made some strides, and it was addressed in the draft,” Shanahan said. “Any time you get a third-rounder, a fifth-rounder and a sixth-rounder and improve a little bit in free agency, you’ve helped the depth of your offensive line. And we’re a little more comfortable with the system. . . . So we do have some competition there as opposed to the last two years.”

Williams said Brown “is down about” his setback because he doesn’t want to let his teammates down. His outlook is one shared by the other linemen, who want to be counted on as a force for the team.

Said Hurt: “The offensive line position is naturally a pressure position because you have to protect the quarterback, and then having a highly-prized rookie quarterback puts even more pressure on you to protect the guy. But that’s what you do. You take it in stride and use it to motivate you. . . . I don’t want to be the one to let him get hit, and nobody else wants to be that guy, either.”