There has been a lot of focus on the changes around the Vikings offensive line as they head into their third season under Mike Zimmer. But don't overlook the turnover on the special teams unit, which in the past year has seen the release of kicker Blair Walsh and the departure of kick returner Cordarrelle Patterson via free agency.

Vikings special teams coordinator Mike Priefer said that it's all part of the game, even if he wasn't happy about losing Patterson.

"Losing a great returner like him, we have to find somebody else that may not replace him, but we need somebody to show up and help us be successful on kickoff returns, like we have been in the past," he said. "I think that was a decision that our front office made and I think that we're going to be fine. We'll survive it. It's like that a lot on special teams, good players come and go.

"Rhett Ellison signed in New York [with the Giants] and Audie Cole signed in Jacksonville and Justin Trattou in Tampa Bay and Cordarrelle in Oakland, Matt Asiata in Detroit. We've had a lot of players come and go, and when you have that bottom part of the roster leave like that, you have to replace them with the young talent that you have. I think we have good young guys that are willing and able and really want to play and contribute on special teams."

Patterson was No. 3 in the league in kick return yardage last season with 792, and his average of 31.7 yards per return was the tops, earning him his second career All-Pro honor. Priefer knows it's going to be tough to replace him. He talked about the candidates.

"I think we have Jerick McKinnon, we have Rodney Adams, we've got Stacey Coley, and of course Marcus Sherels has been a backup here since I have been here so he could be a backup guy at that spot, as well," Priefer said.

In the first two preseason games, Adams has returned five kicks and Coley and McKinnon one each.

And while Priefer said he has been impressed by those three, Adams' fumble at Seattle was not a good sign.

"I'm impressed with their attitude, their effort, their ability," he said. "I think we have a lot of guys that have a lot of ability, but the young guys like Coley and Adams have to get experience. Adams fumbled the one the other night against Seattle and that should never happen and can never happen, that really hurt our football team.

"We have to make sure we secure the ball and have a guy out there that, No. 1, is going to make sure that the ball gets back to the offense in good field position, and No. 2, hopefully a guy that can every now and then get a big play for us, an explosive return or even a touchdown."

Sherels remains a star

Perhaps the most versatile player on the Vikings is Sherels, the undrafted free agent from the Gophers and Rochester John Marshall who has become the go-to player on special teams.

Sherels had four special teams tackles last year, recorded 21 punt returns for 292 yards and two touchdowns and also had two kickoff returns for 35 yards. His 13.9 yards per punt return in 2016 were the second-highest in the NFL.

"The thing with Marcus is that he starts on the kickoff team, he's our starting punt returner, he starts on the punt team as a gunner, so we use him a lot on special teams," Priefer said. "I think it would be a lot for him to do that. He's not a big guy, so he might get beat up as a kick returner. But he is one of our options, and if he's the best option on gameday then we're going to go with it, because I know he's willing to do that."

Starters available

Besides the kicker, punter and long snapper, there are no players on a roster designated only for special teams. Priefer said that the best players to fill out on special teams are often backups to the starters, but that Zimmer does make Vikings starters available to him as well.

"You know a great thing about coach Zimmer is that he allows me to use starters on special teams," Priefer said. "We don't use a ton of starters right now in the preseason, we try to get the young guys ready and see who can be that guy on special teams to help us in the core phases.

"But at the end of the day though, I think we're going to have a bunch of veteran guys at least be backups on special teams. On gameday we only have 46 guys, so we have to get everybody ready to play."

Priefer knows that trying to replace such a large number of players is going to be challenging, but he said that despite all of the great special teams players who left, the team still only went 8-8 last season. And his one goal this year is to help improve that number.

"I can only hope so," he said about improved play from his unit. "At the end of the day, I'm not a big stat guy. I just look back at the games that we helped our team win and the games that we didn't do enough to help our team win.

"We won eight games last year and we were a big part of the wins but also a big part of not doing enough in the losses. At the end of the day we have to play better overall, more consistently, so we can help our team win more than eight games."

JOTTINGS

• Quarterback might be a problem for the Gophers as they are planning to start both Conor Rhoda and Demry Croft, but they did land a solid future starter at that position in Shelby, Ohio's Brennan Armstrong, who threw for 2,321 yards and 21 touchdowns and also rushed for 1,065 yards and 18 scores. "I'm 100 percent committed to Minnesota," he told Rivals.com. "I don't talk to any other schools."

• Despite having one of the best defenses in the NFL last season, the Vikings had only one player listed on NFL.com's 2017 All-Pro predictions — cornerback Xavier Rhodes. The writer, Elliot Harrison, did praise defensive end Danielle Hunter but did not put him on the list.

• Asked to compare Adrian Peterson with Dalvin Cook, Vikings offensive coordinator Pat Shurmur said it's hard to do at this stage of the rookie Cook's career. "I obviously was not around Adrian as much as other people, but he was a downhill, explosive-type runner, one of the best of all-time," Shurmur said. "We've got Dalvin here who's got the traits to be a really good football player, so we'll see how that plays out."

• Pro Football Focus graded out the top players in the Vikings-Seahawks game, and Vikings fourth-round pick Jaleel Johnson, who had five tackles, topped the list with a grade of 86.3.

• The 49ers, the Vikings' opponent Sunday, have had four coaches since 2014 when the Vikings hired Mike Zimmer. They have employed Jim Harbaugh, Jim Tomsula, Chip Kelly and now Kyle Shanahan. Incidentally, Shanahan was born in Minneapolis while his father, Mike, was on Joe Salem's Gophers staff.

• The concussion to Twins catcher Jason Castro could hurt. With him behind the plate (769⅓ innings), Twins pitchers have a 4.21 ERA vs. 5.69 with Chris Gimenez (357⅔).

Sid Hartman can be heard on WCCO AM-830 at 8:40 a.m. Monday and Friday, 2 p.m. Friday and 10:30 a.m. Sunday. shartman@startribune.com