Defensive end Matt Ioannidis works on a drill as teammate Anthony Lanier waits his turn. (Photo by John McDonnell / The Washington Post)

The Redskins’ defensive line will finish the preseason without the starting unit having played a snap together, but optimism remains high with the regular season opener less than two weeks away.

Matt Ioannidis returned to practice this week after a knee injury suffered in the preseason opener kept him out of pads for two-plus weeks. Daron Payne and Jonathan Allen didn’t play in the opener then starred in the second game without Ioannidis.

“We know what those guys can do individually,” linebacker Ryan Kerrigan said, “and now it’s about them working together and getting some reps under their belt so we can see what they can do collectively. There’s a lot of variety in those guys in how they rush and how they play the run. I think that’s good because no one lineman can get too set on what they’ve got to do.”

Ioannidis had 27 tackles with 4.5 sacks and a forced fumble while starting 10 games in 2017. He played 14 games as as the other starters, Phil Taylor and Allen, were both lost for the season. Ioannidis, Payne and Allen will be the starters in base and rotate when they drop to two with an extra defensive back on the field.

The Redskins, who ranked last against the run in 2017, are expecting a marked improvement.

“It’s important for [Ioannidis] to get out there and just get a couple reps in there to get a feel,” Coach Jay Gruden said. “Try to get some running in there for his stamina, but he looks good. He’s probably not quite there yet, but he will be.

“Three guys that can all rush the passer pretty good and they’re all strong against the run. Last year we gave up some big hits in our sub packages in the running game and I think with Matt, Jonathan and Payne, whatever combination we use of those three, I think we’ll be a lot more stout against the run. I think he just adds to the mix, keeps everybody fresh and strong.”

Payne and Allen shined in the second preseason game but took a step back last week against the Broncos. Still, Payne has been disruptive in the middle since arriving and has showed a pass-rush ability that many questioned. Allen has built upon the potential he showed in five games before going on injured reserve last season.

Gruden is one of those expecting big things from the pair and the entire line.

“They’re both strong humans and they’re hard to move and they’re tenacious in their efforts,” Gruden said, “which is really critical for a defensive lineman. When you have talent and you have strength and you’re also tenacious, it’s a heck of a combination and one we feel really great about with those two guys and, really, when you throw Matt in there, he’s the same way.

“[It’s] the same with Ziggy Hood and the rest of the guys have also kind of picked up that mentality in Coach [Jim] Tomsula’s room. We feel really good about where they’re at.”

Injury update

Wide receiver Maurice Harris did not participate in practice again as he continues to be sidelined by a concussion. Gruden said Harris was seeing doctors Tuesday. Harris’s injury puts the staff in a strange spot as he excelled in training camp and the first preseason game, but didn’t play in the next two. The receiver position is one of the most hotly contested after the starting trio of Paul Richardson, Jamison Crowder and Josh Doctson. Trey Quinn, Harris, Brian Quick and Cam Sims are vying for the final three spots, and Quinn is probably already in.

Zach Brown (oblique) and Colt McCoy (thumb) also did not participate. Trent Williams sat out with a veterans rest day.

Samaje Perine (ankle) was back fully for the second consecutive day, and Gruden said he will play in Thursday’s game against the Ravens. The second-year back is in a similar position as Harris at a competitive position. The Redskins likely will keep four running backs, and Adrian Peterson and Chris Thompson are secure. That leaves Perine, Rob Kelley, Byron Marshall (ankle) and Kapri Bibbs fighting for the two remaining slots. Perine and Marshall missed the third preseason game because of injuries suffered against the Jets in the second preseason game.

“Everybody understands the competition at every position,” Gruden said. “Those conversations have taken place. Samaje has been unavailable as of late, so now it’s important for him to get back in there and make a run and Rob the same thing.

“Competition’s still there. They know what’s up. They’re pros.”

Looking ahead

While a large number of players try to make one more impression this week, the starters are looking ahead to the start of the regular season. Kerrigan said it’s a balance since there’s not the full-out game-week preparation for the Arizona Cardinals, but veteran rotation players have turned their attention to Sept. 9.

“Preparation, staying physically and mentally sharp,” Kerrigan said. “We’ve had some tough days these past couple days of practice. We’ve had a lot of reps and it’s been really freaking hot and humid out.

“We’re going to be ready physically. Now it’s about us staying locked in mentally and get an early start on Arizona. We’re getting started on that. Guys individually starting to watching film and making their own little mental notes. Don’t have a lot of film to go on right now just because it’s preseason and a new coach. We’ll just have to work with what we’ve got.”

Read more on the Redskins:

Redskins defense gets a ‘wake-up call’ after disappointing showing vs. Denver

Adrian Peterson is lone bright spot in Redskins’ 29-17 preseason loss to Broncos

Clinton Portis says Adrian Peterson wearing No. 26 shows ‘a lot of respect’

Kapri Bibbs says he loves having Adrian Peterson as a teammate: ‘This man is a role model’

After one hit ended his Redskins career, Kyshoen Jarrett coaches with hopes of a comeback