EAGAN, Minn. — Recurring problems for the Vikings defense in 2020 included a lack of results against the run and subpar success at disrupting passers.

Minnesota opened 2021 free agency by addressing those glaring needs out of the gate, reaching a deal with Dalvin Tomlinson.

In 2020, the fourth and final season of his rookie deal with the New York Giants, Tomlinson posted career highs of eight tackles for loss and 10 quarterback hits.

While Tomlinson is considered by some to be more of a nose tackle than a disrupting 3-technique like the Vikings added when they signed Sheldon Richardson in 2018, Tomlinson led the Giants in tackles (207) and tackles for loss (21) since joining New York in 2017 as a second-round pick.

The Vikings lack of experience at cornerback showed up early in 2020 and throughout the course of the season, which marked the first time for Minnesota to start two rookie corners since 1999.

Minnesota wanted to add experience at the position during free agency, but didn't fully expect that Patrick Peterson would be a possibility. Once General Manager Rick Spielman received word that Peterson would be available, the Vikings shifted plans on the fly to recruit the three-time First-Team All-Pro who ranks tied for fourth among corners in NFL history with eight career Pro Bowls.

Neither Tomlinson (64 games in four seasons) nor Peterson (154 games in 10 seasons) has missed a start because of injury. Those two "intriguing additions" are poised to enhance the impact of expected returnees that missed all, most or significant parts of the 2020 season that ended with Vikings Head Coach Mike Zimmer publicly stating his frustrations with his beloved unit.

"This is a bad defense," Zimmer said on Christmas Day after a loss to the Saints. "The worst one I've ever had."

Of course, it will help that defensive tackle Michael Pierce and defensive end Danielle Hunter — who played a combined zero snaps in 2020 — are expected to return. (Pierce opted out of the season due to COVID-19, while Hunter suffered a season-ending neck injury in training camp).

"I think those two would help for sure," Spielman said earlier this month on March 3. "That's almost like adding two free agents to this year's class."

And two weeks after making that statement, Spielman and the Vikings poured more resources into the defense.

Can you tell Zimmer was irked by how his defense performed in 2020?

Even Peterson said he got that vibe around Twin Cities Orthopedics Performance Center on Monday morning.

"One thing I can say after competing against Coach Zimmer's teams is they're going to be well-prepared, his teams are going to be competitive and his teams are going to be relentless," Peterson said. "Having an opportunity to be recruited by Coach Zimmer to be drafted in 2011 when he was a defensive coordinator in Cincinnati, and having the opportunity to pick his brain and see the history and his track record with some of the guys he was able to work with in his very long NFL career, it just made sense to me because I feel like I have a lot left in the tank.

"Every cornerback or every defensive back that Coach Zimmer had an opportunity to help take their game to the next level, he's done that. His defense itself is always in the top-10. I think last year was probably his worst finish since he's been here as a head coach," Peterson added. "And just the tenacity that his team has when they step onto the football field on Sunday, it just goes to show that his teams are well prepared and they have a relentless mindset that is undeniable. That's why I wanted to be a part of this organization."

Peterson will undoubtedly be tasked with helping a young cornerbacks room show growth and improvement in 2021. Jeff Gladney and Cameron Dantzler combined to play 1,559 defensive snaps as rookies in 2020, but 2018 first-round cornerback Mike Hughes has played just 915 total snaps in three seasons due to injuries.

Peterson has 9,000-plus defensive snaps on his resumé, which also includes a spot on the Pro Football Hall of Fame's 2010s All-Decade Team.

"There's no question what his qualifications are on the field, and I know how excited Coach Zim' is, and our defensive staff is, to start working with him and the experience he's going to bring to our young group on the back end," Spielman said. "But I also know that he has a lot of football left, and usually, when you bet on guys that have the pedigree that he has, you're going to get some outstanding football going forward.

"I know that he has a lot to prove to a lot of people," Spielman added. "He didn't have anything to prove to us, because we already know what type of football player he is."

The 30-year-old said he's more than ready to help mentor a group of young but promising cornerbacks.

"First and foremost, it starts with yourself. You have to be able to self-evaluate, understand what you can do well, understand what you need to work on, and then that's when you can start worrying about the playbook, understanding the playbook a little bit better," Peterson said. "Then after you understand the playbook, learn how to study your opponent. Then after you learn how to study your opponent, learn how to practice, because I have a saying that you practice how you're going to play.

"I've been in the league for 11 years now, I've seen guys come in and take practice like a joke on a Wednesday or a Thursday. The next thing you know, that comes up on Sunday because on Wednesday you didn't take it serious. It's just little things like that. Taking the walk-through seriously … everything that is scheduled is for a reason. While you're on the football field, classroom or wherever it may be, you want to take it serious and put your best foot forward at all times."

Minnesota ranked 25th in the league with 258.8 passing yards allowed per game in 2020. The Vikings were tied for 23rd with 30 passing touchdowns allowed and also recorded a franchise-low 23 sacks since the stat became official in 1982.

The run defense was actually worse in the rankings, as the Vikings were 27th with 134.4 rushing yards allowed per game. And Minnesota was 24th with 19 total rushing scores given up.

Enter Tomlinson, who should form a formidable duo with Pierce on the interior of the Vikings defensive line.

"He plays with great leverage, has great strength at the point, excellent with his hands, does a great job getting off blocks and firing at the ball, making plays all over the field in the run game," Spielman said of Tomlinson. "I think the thing that he doesn't get enough credit for is — when you sit down there and actually break down the tape — how he still affects the quarterback.

"Even though he may not have the gaudy sack numbers, he collapses the centers, he collapses the guards, it gets the quarterback off his spot in the pocket, which can create a lot of pressure different ways," Spielman added.

The 27-year-old Tomlinson said he's ready to come in and make an impact in Minnesota under the tutelage of Vikings Co-Defensive Coordinator/Defensive Line Coach Andre Patterson.

"Coach Patterson is a great defensive line coach," Tomlinson said. "I remember him talking to me when I was at the Combine. It felt like yesterday, but it was four years ago.

"A great, tremendous coach. You can just tell from his track record of the defensive linemen he's had, and I'm super excited to play for him," Tomlinson added. "I can't wait to put these pads on and get out there and let him coach me up a little bit."

The 2020 season was a frustrating one for all involved with the Vikings defense.

Injuries, missed games and inconsistent play all contributed to a unit that didn't perform up to Zimmer's lofty standard.

But as we cruise toward the end of March, there's good reason to believe the 2021 season should be a bounce back year for the defense.

"You got Anthony Barr, Harrison [Smith], myself, D-Hunter. I know I'm forgetting some people, but we're loaded," Peterson said. "If we can come in here and stick to the three core values around here — unity, commitment and relentless — and you get all 53 guys on the same page for [every] game … we have a chance to do something pretty special."