When backup Vikings linebackers were struggling on defense and special teams during the preseason, co-defensive coordinator Adam Zimmer said the "train is leaving" to convey the urgency he wanted to see from the position.

Nick Vigil, Blake Lynch and company caught the train, easing concerns about the position's depth just as it nears full strength. Vigil, a sixth-year journeyman, impressed in his four starts for linebacker Anthony Barr, who was a full participant again Thursday ahead of his expected return Sunday against the Lions. Barr will return to his full-time role, moving Vigil to just weak-side linebacker duties in the base defense.

"He's still going to play," Barr said. "He'll definitely get his reps. He's a great player."

Vigil had 30 tackles (two for a loss), an interception returned for a touchdown and a sack in four starts. Barr, playing in his first game in 13 months, will have his conditioning monitored. But coaches are confident he can handle a normal workload right away.

"He started to get over that hump in practice," Zimmer said. "He's taken a lot of reps now, and I think he's comfortable getting his sea legs back."

Linebackers Troy Dye and Ryan Connelly have impressed on special teams. Lynch, a second-year undrafted linebacker, has received solid grades from coaches in back-to-back weeks while filling Barr's role as the strong-side linebacker in the base defense.

"[Lynch] really had his best game against Cleveland," Zimmer said. "He was more physical, got off the blocks and made some plays. He works his tail off, and I've always seen potential in him. I've just wanted to see it on tape, and I think, especially the last two weeks, I think he's found his way with it a little bit."

Cook, Pierce remain sidelined

Running back Dalvin Cook again joined his teammates for warmups and running back drills at the start of Thursday's practice, but the Vikings listed him as officially not practicing due to his sprained right ankle. The plan, according to Cook, is to continue to play through the injury after he was limited to 11 touches in 33 snaps against the Browns.

Nose tackle Michael Pierce (elbow) and receiver Ihmir Smith-Marsette (toe) also did not practice. Cornerback Kris Boyd practiced fully and is expected to return from a one-game absence stemming from a pulled hamstring.

Kicker Greg Joseph remains a full participant with a right hip injury, which won't affect his range against the Lions, special teams coordinator Ryan Ficken said.

'Get his conditioning up'

The Vikings' first-round pick, left tackle Christian Darrisaw, is off the injury report, but he's still physically returning to form. The 22-year-old rookie is in his second full week of padded practices. He'll continue to be a backup in the meantime. Darrisaw played one snap — an extra point — in his first game against the Browns.

"Just trying to get him into football shape and get his conditioning up — his football conditioning — because you can't do that without going out and doing it and practicing," offensive coordinator Klint Kubiak said. "Making sure we give him a solid foundation so that when that times comes, he's able to be at his best."

Through four games, no NFL team has fewer snaps from rookies than the Vikings, according to Pro Football Focus. Rookies have contributed just nine snaps on offense or defense — five from safety Cam Bynum (five) and four from Smith-Marsette.

Dantzler, Hand could return Sunday

Cornerbacks Cameron Dantzler and Harrison Hand could be activated from the reserve/COVID-19 list by kickoff on Sunday, according to Zimmer, but whether they test their way through the league's return protocols remains to be seen.

Dantzler, as a vaccinated player who tested positive, needs two negative tests taken 24 hours apart. Hand's status is unclear. If he's an unvaccinated close contact, his second stay on the COVID list is a minimum five days with negative daily tests.

"That's something that's kind of ongoing, whether they're going to be back," Zimmer said. "But for this game, we're unsure right now. It's just the way it is."

Can you hear me now?

Center Garrett Bradbury's job of yelling out the Lions' middle linebacker and adjusting protections will be a key against a Detroit defense that's a base 3-4 front but shifts into varied alignments and can throw off an offense's plans. Bradbury has been credited with cleaning up pre-snap communication issues in the Week 1 loss at Cincinnati.

"If we all are on the same page, we can be really explosive and get in that rhythm that we want to be in," Bradbury said. "Communication is huge. It's a benefit that we're at home and when we have the ball, it's not as loud."