The Monday morning film sessions begin at 5:30 a.m., when Mike Zimmer congregates with his coaching staff to study for the Vikings’ next opponent and review the previous day’s game in search of the plays that hurt them.

Early this season, those film sessions revealed a pattern: Every team the Vikings were about to play had the same approach.

“I guess the best way to say it is when you’re watching these other teams, the offenses you’re getting ready to play, and they’re all attacking with basically the same combination, route combination and things,” Zimmer said. “You see it’s vs. that particular style of coverage. That’s when it really shows up. You see everybody game-planning the same coverage every single week. That’s why we’ve had to change.”

Embedded in those film sessions could be the secret to why the Vikings have turned their season around. Their three-game winless streak reached its nadir Sept. 27, when Jared Goff threw for five touchdowns in a Thursday night game that prompted missives about whether the Vikings defense had been figured out. Since then, the Vikings have won four of five games, allowing only 274.8 yards and 18.8 points per game while reclaiming their title as the league’s best third-down defense.

While their defensive struggles certainly could be attributed in part to the absence of three-time Pro Bowler Everson Griffen and the adjustment period that came as they turned to young defensive backs such as Mike Hughes and Mackensie Alexander, the Vikings also found themselves needing to adapt. As concepts they’d popularized, like double-A gap blitzes and pattern-match coverages, became common around the league, so did the formula for attacking those concepts. The Vikings, in some ways, had become victims of their own success.

“I love watching film with Zim on Monday mornings at 5:30 because he is very smart on seeing what’s happening,” General Manager Rick Spielman said, “and I know he spent hours and hours on how offenses have adapted to some of the things we’re doing on defense and how other teams have copied. There’s a lot of smart people in this league, and in order to keep moving forward, you just can’t keep getting hit in the head with the same thing.”

The Vikings began to depart from their double-A gap blitz package during the 2017 season; this year, Zimmer said, “I don’t think we’ve run hardly any double-A blitzes.”

Instead, they’ve incorporated a new suite of overload blitzes, taking advantage of the flexibility created by their increased use of various nickel packages. Harrison Smith’s three sacks are the second most in the NFL among safeties, and Alexander’s three sacks tie him for the league lead at his position.

A new strategy

“What that’s allowing them to do is force that protection to slide to the overload slide, and now they’re getting free runners on the backside,” said ESPN NFL analyst Matt Bowen, who played seven years in the league as a safety. “The sack Alexander had against the Cardinals — he was about seven yards off the ball. If I’m a quarterback, I would not expect him to come from that alignment. No way. But he did. And that’s why they didn’t switch the protection — because it looked like they’re in coverage. Eric Kendricks rolls down, he bounces back, and all of a sudden Alexander comes, and there’s a wide-open lane.

“That’s what they’re doing more — they’re showing overload pressure, not just standard double-A pressure. A lot of teams around the NFL have seen that for so long. Everyone’s kind of caught on to that. So how are you going to use those linebackers? Now you’ve got a different look up front, and your entire theory behind that is to get the protection to slide to you — and have guys assigned to you, and you’re not coming. But to do that, you’ve got to hold those disguises, and they’re so talented at holding those disguises, and getting back.”

What’s more, the Vikings blitzed quarterback Matthew Stafford only five times against the Lions, getting nine of their 10 sacks from their four-man front that’s improved now that Griffen has rejoined the group and Stephen Weatherly has established himself.

“That’s the best thing in the world,” Bowen said. “You want to be creative. You want to challenge people — but you don’t have to. They have a deep rotation, and that, in my opinion, goes back to the team that won the Super Bowl last year: the Philadelphia Eagles. You can continue to throw fresh legs on the field, continue to rush the passer. At the end of the day, as a coach, you’re loving that, because then you can protect yourself from a coverage perspective.”

Still some flaws

Bowen didn’t necessarily subscribe to the theory the Vikings defense had been figured out; the Rams had the perfect play call to exploit the Vikings on Cooper Kupp’s 70-yard touchdown in Week 4, he said, but many of the Vikings’ other issues that night were a product of the Rams’ exemplary talent.

“A couple of those are just great throws,” he said. “You start with the first touchdown to [Todd] Gurley, where you’ve got him matched up against Anthony Barr. I would never expect a team to run the seam route that deep in the red zone — but they did, and they got Anthony Barr.”

Still, the Vikings likely will continue to be tested with some of the same misdirection concepts they saw early in the season, beginning Sunday night against the 6-3 Bears. Chicago uses many of the concepts from Kansas City’s jet-powered offense, now that former Chiefs offensive coordinator Matt Nagy is the head coach in Chicago.

“Chicago is [Chiefs coach] Andy Reid and [Eagles coach] Doug Pederson’s offense,” Bowen said. “There’ll be a lot of movement. There’ll be guys like Tarik Cohen, who go in jet motion and different formations, and a tight end in Trey Burton who can align anywhere on the field. When they use ‘21’ personnel, which is two running backs in the game, it’ll be Jordan Howard and Tarik Cohen, to try to gain a pre-snap advantage — one that helps the young quarterback in [Mitch] Trubisky, and gives them an opportunity to create some open windows.”

Finding a new way

But if the Bears assume they’ll be able to copy the blueprint the 49ers and Rams used against the Vikings — or, for that matter, the one the Eagles used to beat them in the NFC Championship Game — they’ll find a Vikings defense that has evolved. When the Lions tried to run the type of rollout screen the Rams used on Goff’s 56-yard completion to Gurley, the Vikings snuffed it out twice.

“We’ve had to make adjustments on how we’re playing that,” Zimmer said. “[Last Sunday] I think they [the Lions] lost yards on both of them.”

The Vikings will have to continue to adapt. But as they’ve shown already this season, they can reorient themselves in an effort to regain the upper hand.

“Think about it this way: The Vikings had one of the best defenses in the NFL last year,” Bowen said. “So if you’re an NFL offensive coordinator, one of the first tapes you’re going to watch in the offseason is the Vikings. I’m sure opposing offensive coordinators studied them like crazy this offseason.

“Nothing is unbeatable in football. Were they figured out? I don’t want to say they were figured out, but teams found a way to create matchups and open throwing windows against them. What happens from the perspective of the Vikings is, you go back and say, ‘How are teams beating us? What can we do differently? What can we do to correct it?’ ”


Ben Goessling covers the Vikings for the Star Tribune.E-mail: