Kory Lichtensteiger was moving with special care in the Washington Redskins’ locker room on Sunday following the 20-13 loss to Philadelphia, his right leg immobilized and a pair of crutches on the floor next to the chair in front of his stall. The starting left guard drew several deep breaths as he zipped his luggage, and teammates and members of the equipment crew offered encouragement and assistance with his belongings.

The reality of apparently torn knee ligaments clearly was weighing on Lichtensteiger, who was forced from the game before it was even three minutes old. The potential season-ending injury compelled a retooling along the line that affected the entire offense.

“It’s definitely the worst moment of my football career,” said Lichtensteiger, whose injury forced center Will Montgomery to move to left guard and reserve Erik Cook to come in at center.

A few feet away, left tackle Trent Williams was dealing with his own leg injury. The initial diagnosis was a high ankle sprain. Williams was wearing a walking boot on his right foot but vowed to be back in the lineup as soon as possible.

The No. 4 overall pick in 2010 had reacted immediately on the field when he witnessed the injury to Lichtensteiger that, by Williams’s account, occurred on a tackle well away from Lichtensteiger. Quarterback Rex Grossman had thrown an interception, and Lichtensteiger was trying to locate the ballcarrier when, according to Williams, linebacker Darryl Tapp tossed him to the ground.

The nature of the block so infuriated Williams that he drew an unnecessary roughness penalty seconds later. Then, less than two minutes into the second quarter, Williams was receiving attention on the field for his injury before he departed and was replaced by Sean Locklear.

“The dude just tried to grab him and throw him down,” Williams said. “The ref was looking right at it. He failed to make the call. It was a dirty play to begin with. Unfortunately, we lose him.”

Offensive line instability and a 20-0 deficit conspired to limit the Redskins to 42 rushing yards, by far their worst showing this season. That lack of production was especially confounding because the Eagles entered the game ranked 30th against the run, giving up 140.2 yards per game.

Washington entered ranked eighth in rushing at 126.8 yards per game. Ryan Torain finished as the team’s leading rusher with 22 yards on 10 carries. Second was quarterback John Beck, who played only the final quarter, with 14 yards.

The pass protection suffered too, noticeably on third and long, when Eagles defenders were able to harass Grossman. Late in the first half, for instance, defensive tackle Mike Patterson beat Montgomery for a sack on third and 11. The loss went for eight yards and pushed Washington back to the Eagles 32, where place kicker Graham Gano connected on a career-long 50-yard field goal.

“Guys, they’ve been playing pretty much since the preseason, getting that chemistry together, and we know that’s a huge part of the game,” Locklear said. “We as backups, we’ve got to come in and prepare as if we were starters. It’s still different, but we can’t use that as an excuse.”