After four months without football following his release from the Oakland Raiders in March, offensive lineman Donald Penn arrived at Redskins training camp July 31 with a chip on his shoulder and a position battle to win. Over the course of the past 28 days, he's accomplished just that.

Speaking after practice Monday, head coach Jay Gruden announced that Penn is currently the team's starting left tackle. He then spoke to what the 36-year-old offensive lineman can add to the starting unit entering his 13th NFL season.

"He's seen a lot of football, played a lot of football; he knows how to set on these guys," Gruden said. "He's not quite where he was when he was 22 years old, but he's still a very functional left tackle in the NFL."

At his introductory press conference, Penn stressed he only signed with Washington because he had a chance to start at left tackle in Trent Williams' absence. This was Penn's natural position and one he played his entire career until last season, when the Raiders moved him to right tackle. Penn admitted he wasn't nearly as comfortable there.

The Redskins immediately inserted Penn at left tackle during training camp, and they've rotated him and Geron Christian with the starters in the weeks since. Eventually, Penn gained separation. He started the third preseason game against the Falcons on Aug. 22, and now he'll prepare with the first unit ahead of Week 1 in Philadelphia.

"I like the pieces they have," Penn said in late July. "It looks like they have been working hard, and I'm just trying to pick up so it doesn't look like I am slacking. I am just trying to go unnoticed and just keep working with them. We got a good thing going because if we didn't, you know I am going into my last year. I'm not just signing to play, I'm signing to win."

A three-time Pro Bowler with 178-career starts, Penn offers a wealth of knowledge and experience along a starting offensive line unit with no one over the age of 28. Plus, going up against a youthful Redskins defensive line every day has helped the 6-foot-4 Penn quickly work back to game shape after finishing the last two seasons on injured reserve. "I'm not there yet," Penn told reporters after practice Monday, "but I'm still working to get there."

As the years have passed, Penn has adjusted his game to handle the new breed of speed rushers in the NFL. He's specifically focused on his hand quickness to prevent defenders from ripping, dipping or spinning past him.

One of the young pass-rushers Penn has frequently squared off against is first-round rookie Montez Sweat, a 6-foot-6, 262-pound edge defender with a unique blend of size and speed. Penn said Sweat reminds him of a young Khalil Mack -- who is an All-Pro outside linebacker with the Chicago Bears -- and has a frame similar to defensive end Julius Peppers.

"[Sweat] looks a lot like Julius Peppers," Penn said, referring to the nine-time Pro Bowler. "You see how long his arms are? Man, he can scratch his knees standing up."

Penn has been impressed with the young offensive linemen, specifically 2019 draft picks Wes Martin and Ross Pierschbacher. Before taking over the starting job, Penn primarily played next to Martin, who plays left guard with the second team.

"I've mostly worked beside Martin and he's looked really good, he's really strong," Penn said. "I've worked with some other rookies along the line, too. Ross [Pierschbacher] has looked solid as well."

To further prepare Penn and the other Redskins offensive linemen, offensive line coach Bill Callahan created a customized sled that simulates the height, weight, and angles presented by down linemen. It also includes a back plate to allow linemen to engage and grab the sled as they would in game action. The contraption is something Penn said he has never used before and one he believes will benefit the unit as a whole.

Despite playing more than a decade in the NFL, Penn defended his ability to produce. The reps beside an influx of youth on the Redskins line has provided Penn a burst of excitement and energy, which he'll look to unleash against the Eagles on Sept. 8.

"Football is football," Penn said. "At the end of the day, I'll get my body set and ready to go."