RICHMOND, Va. -- On the first rep in a pass-rush drill, Ryan Anderson sped around the Washington Redskins' current starting left tackle. It provided a reminder: Ereck Flowers is not Trent Williams. And Williams is not in Richmond, leaving Flowers as the starting left tackle. For now.

Flowers later stopped Anderson on another pass rush and was fine during full-team drills. But throughout Williams' tenure, there's one thing that has rarely happened: Williams getting beat in a one-on-one pass-rush drill.

But with Williams holding out, the Redskins have to deal with reality. Coach Jay Gruden expressed optimism Williams would return, but there's no telling when that will happen. Or if it will happen.

Williams, according to sources, is upset with how a growth on his head was treated over the years. It was finally surgically removed this offseason. Sources within the Redskins say several appointments for him over the years weren't kept. It's unclear whether a new contract, or more guaranteed money in 2020 -- the last year of his current deal -- would appease Williams.

For the players, though, it's not about whatever beef exists; it's about simply missing a teammate.

"It's weird not to have him here," said linebacker Ryan Kerrigan, a teammate since 2011. "I obviously hope everything works out and that he's back here. He's not only an elite offensive tackle, he is the best offensive tackle in the game, and I know a lot of guys will say that their teammate is [the best in the game] but I can say with confidence that Trent is that. We need him on this team. I hope he's back here sooner than later."

Redskins tight end Vernon Davis, entering his 14th season, is like most of the players: He understands it's a business.

"We wish we had Trent," Davis said. "But when you're playing ball, you have to continue to keep moving. If one guy isn't here, you have to find someone to replace him. But it's hard to find someone to replace Trent Williams. We all know how good he is."

The Redskins are used to replacing guys, having placed a combined 52 players on injured reserve the past two seasons. They are bringing in Donald Penn for a workout Friday.

"The way the NFL goes, if you're not here, someone has got to step up," Redskins defensive lineman Jonathan Allen said. "If I go down, it would be tragic, but the next defensive lineman has to step up. Everyone is out here competing for their job every week, every year, every day. People forget it's a business. It sucks to hear, but it's a business -- a tough business at that. I'm wishing him the best. Hope he's doing good, but I don't know any more beyond that."

For now, the next man up is veteran Flowers. Like Williams, he was a first-round pick -- in 2015 with the New York Giants. But Williams has made seven straight Pro Bowls; Flowers is with his third organization. The Giants cut him last year, and Jacksonville signed him late in the season. He signed with Washington thinking he would be moved to left guard.

Those plans are on hold. The other possible option at left tackle is second-year player Geron Christian, but the 2018 third-round pick is coming off a torn MCL and missed the offseason practices. So Flowers remains the best option. But if he has to stay there, it would mean possibly playing him next to a rookie left guard in Wes Martin. The Redskins' line looks dramatically different minus Williams.

While fans can bemoan Williams' absence, for Flowers it's an opportunity. He was roundly criticized in New York, where he played for three offensive line coaches in four years.

"I had a breath of fresh air from the moment I left [New York]," he said. "That's OK; I learned a lot there. I grew as a man there."

He said he's a different player than he was in New York after working with Redskins line coach Bill Callahan. For one thing, Flowers said he varies his sets more than he has in the past.

"As opposed to just kicking back," he said. "I've done that most of my career and it hasn't been effective."

But Flowers understands the spot he's filling.

"Great player, Hall of Famer," Flowers said of Williams. "I don't know about it; I just got here. I'm just doing what they're asking me to do and wherever they want me to do it."

For now that means filling in at left tackle. The Redskins are hopeful that won't be the case when the season begins.