Tyler Polumbus (74) signed with the Redskins as a free agent last November. (Jonathan Newton/The Washington Post)

 Brown was projected to enter his third straight season as Washington’s starting right tackle, but on the eve of training camp, he re-injured his surgically repaired right hip — which has hobbled him in each of the last two seasons. Brown last Thursday had surgery to repair what turned out to be a torn ligament in the hip and on Monday was placed on the Physically Unable to Perform list for the regular season. That means that the earliest that he would be available to the team would be after Week 6, although the team has until Week 10 to evaluate him and decide whether to activate him, place him on injured reserve or cut him.

 Polumbus, who signed as a free agent last November and went on to start four games, splitting time at left guard and right tackle, has worked as the first-team right tackle since Brown’s injury.

The 6-foot-8, 305-pound Colorado product broke into the NFL as an undrafted rookie with Shanahan’s Denver Broncos in 2008. He later spent time with the Seattle Seahawks, who run the same zone-blocking scheme as Shanahan ran in Denver and now uses in Washington. So he has a good understanding of the offense and his responsibilities.

 Polumbus had some struggles early in the preseason, but on Saturday had his strongest outing yet. Shanahan said the fifth-year veteran has his confidence as the starter.

 “Tyler has done a very good job and I am happy with where he is at,” the coach said. “Unless there is a miracle that happens, he should be starter at right tackle.”

 Shanahan sounded less certain about Brown’s comeback chances. This is the second surgery he has had on the same hip since 2009, and he hasn’t played a full 16-game season since. “Yeah, you really don't know,” Shanahan said. “He's saying right now that the surgery really helped him and that he's feeling really good, so you just keep your fingers crossed that he's able to come back sooner than later. . . . You're always hoping that a guy's going to come back, but it’s bothered him for a while, so you're keeping your fingers crossed that his surgery is going to help him.”