With two Pro Bowlers leading the way along with the recent contract extension for Morgan Moses, the Redskins' offensive line heads into the 2017 season as the foundation for a talented unit.

For now, it appears the Washington Redskins will enter the 2017 regular season with the same starting offensive linemen from a year ago. It's easy to see why the Redskins would once again roll with Trent Williams and Morgan Moses at tackle, Brandon Scherff and Shawn Lauvao at guard and Spencer Long at center.

Last year, that combination started seven games together and were the guiding force behind an offensive unit that featured two 1,000-yard receivers and quarterback Kirk Cousins nearly hitting the 5,000-yard passing mark.

But while the starting five along the offensive line is collective young – Lauvao is the oldest at just 29 years old – assistant head coach/offensive line coach Bill Callahan believes they can grow in "every area."

"I think the offseason is about that," Callahan said. "Then when you go back and look at scheme evaluation and you really study yourself and you go back and look at your strengths and weaknesses and try to grow upon them and build on things that you could've done better, I think we addressed that. I think we were really intense on trying to find all the nuances to get in practice and to enhance our line play.

"Our group is a hard working group and it continued through this offseason. We have a long way to go yet, but I'm really proud of these guys [considering] where they've come from to where they're at. They're always evolving, they're always improving, learning, and trying to maximize their talents."

Of course, it would be difficult to mention the offensive line without first mentioning Williams, a five-time Pro Bowler.

The 2010 first-round pick is entering his eighth season with the Redskins but may be in the best shape of playing career to date. During offseasons now, Williams trains at his gym shared with Adrian Peterson in Houston, where he grinds through rigorous full-body workouts that include boxing.

"He's challenged a little bit differently from the other players because he is a talented guy," Callahan said. "He does see the greatest defensive ends in the league. He's got to have a repertoire of techniques and strikes and moves and throws that he can change up so he's not giving somebody the same move all the time. …He doesn't get into a rut with his hands or his techniques. He's not always showing the same angles on his sets. So we really try to change him up. It's like a great pitcher—they have the fastball, but they have to learn how to throw the slider and the controller curve better and get into some pitches. It's really similar to that."

For the third straight season, Moses will work opposite of Williams. The 2014 third-round pick has been impressive the past two years at right tackle, starting all 32 regular season games despite dealing with a string of injuries.

With his rookie contract set to expire after this season, Washington didn't want to run the risk the potential of Moses testing free agent waters. So on the day the first round of the 2017 NFL Draft was taking place, the Redskins signed Moses to a multi-year extension.

"He's really come a long way," Callahan said. "I just love him—everything about him. He's mindful about everything in his preparation, he's great in the meeting room, he's great with the young players, he can help players at other positions, he can see well in so many respects and, of course, he's going to execute. He's gone against some of the top defensive ends in this league and he's faired pretty well."

At center, meanwhile, Long transitioned into the role well last season after Kory Lichtensteiger went down with an injury in Week 3. The Nebraska product started 13 games at guard for the Redskins in 2015, but tacked on center duties last offseason.

"It's probably the most difficult task in offensive line play because it requires the most communication and having the ability to echo every signal [and] line call," Callahan said. "And it's easy if someone just stands there, you can make a call on a real static front, but there's so many other variables that are moving, that are constant, that are changing the picture, and he's got to be able to flow with that and communicate that on the run."

One way in which the transition was so seamlessly for Long, though, is the fact that all of the guards on Washington's roster are cross-trained as centers.

"They need to be developed with crossover roles because of the activity that you have up on a game day," Callahan said. "So if you're getting seven guys up, they have to have some versatility to swing from a right guard to a center, play like Spencer did in the Giant game [last year] when he was playing guard and then Lauvao went out, then Lichtensteiger went out and we ended up moving Trent to guard and Spencer to center. So, there's a lot of juggling going on and those guys handled it great, let me tell you."