When it came time for him to reach for the red marker and correct the work of his young offensive assistant, then New England Patriots quarterbacks coach Bill O’Brien opted for a joke. Despite his nickname—Teapot—O’Brien insists his default love language is a kind of ribbing humor, which prompted him to hand Brian Flores’s first few projects in New England’s QB room back with the quip: “Come on, man, I thought you graduated from Boston College?” 

“We spent a lot of time together that year,” O’Brien, now, ironically, the head coach of Boston College, says about a seldom discussed but vitally important 2010 season in which Flores, now the Minnesota Vikings’ defensive coordinator, was subject to New England’s Karate Kid–style coach cross-training process in an offensive room for a team that won 14 games and finished first in total points. “Go break down these 100 games, all these opponents we’re going to play the following year. He had to break everything down, down to the blocking scheme. So after you do that for a long time, you really understand a lot about football.”

As the Vikings roll into Sunday’s winner-take-all matchup for the NFC North and NFC’s top seed—against a record-breaking Detroit Lions offense—they do so buoyed by the NFL’s best defense in terms of turnovers, second-best in terms of points per drive allowed and best in EPA per play. As evidenced by last week’s victory over the Green Bay Packers in which the Vikings completely shapeshifted into a physical man defense, showing the coverage more than they had all season and especially on third downs—after recording a season low of the coverage against the Packers a few months earlier—the reality is that there is no Flores defense that one can simply carbon copy. 

According to those around the league who have watched the scheme, it is instead a fluid series of ideas that starts with the very general ethos that a good defense must crawl into the circuit box of an offense and start ripping out wires one by one. On its face, a team can generally expect split safeties and five- or six-man fronts and some kind of flourish with a defender approaching the line of scrimmage presnap, and either dropping back into coverage or adding to the pass rush. But within that simple facade is an understanding of offensive football that Flores rarely gets credit for. 

This season has been a kind of magnum opus for the former Miami Dolphins head coach that has put him back at the top of many prospective head coaching lists at a time that this particular skill set is coming to light as a prerequisite for the modern candidate. Last year, for example, Mike Macdonald became a head coach after building a résumé that began with the Baltimore Ravens as a coach who suggested third-down blitzes based on his study of opposing offensive tendencies. Houston Texans offensive coordinator Bobby Slowik became an integral part of the Shanahan clique by spending three seasons as a defensive assistant and another handful of seasons as a game film analyst for the football site Pro Football Focus (Kyle’s father, Mike, told Kyle that Slowik should be one of his first hires specifically because of how Slowik was able to view opposing offenses from a defensive perspective). Ejiro Evero (a former San Francisco 49ers offensive assistant turned defensive coordinator) and Arthur Smith (a four-year defensive assistant turned offensive quality-control coach) are also top-coaching candidates who have developed their own personal styles based on a hybrid-learning process. While it sounds basic and elementary, the league is still largely divided between coordinators who produce a designer game plan based on attacking specific weakness of an opponent and a game plan that is largely a kind of personal signature based on what those coaches have been historically successful with (indeed, some defensive coordinators struggle to draw a play the way we are accustomed to seeing it on a white board, given that they always draw the defense first).  

“His knowledge of protections and his ability to do things like, take away an opposing No. 1 receiver, he learned that here and he’s taken it to another level based on his own knowledge,” O’Brien says. “Going against certain guys in the NFL, you just knew, this guy knew what he was doing. Baltimore. Jim Johnson in Philadelphia. Rex Ryan. When you went against those guys, they knew who you were relative to some other guy. 

“If you’re getting ready to play Brian, you’re not going to see what you’re going to see on film.” 

Pittsburgh Steelers head coach Mike Tomlin hired Flores in 2022, after Flores’s tenure with the Dolphins ended, knowing little about him. Of course, even to this day, he can remember the moment that Flores truly climbed onto his radar.

“The Dolphins-Ravens matchup in 2021 when he zeroed Lamar Jackson like 39 times,” Tomlin says. “He was bold enough to try something different. A lot of people since that time have mimicked that.”  

By “zero” Tomlin is referring to a highly aggressive defensive front called a Cover Zero, in which the defense does not present with a safety and the few remaining defensive backs left on the field have to pick up the receivers in man coverage. In essence, your defensive front looks like the start of an NCAA cross country meet, with a bunch of people lined up in a sprinter’s stance ready to hurl their bodies forward. 

It looks a little bit like this: 

Tomlin erred in only one part of his recollection: Flores ran the look 40 times and blitzed out of it 34 times, with 24 of those involving defensive backs. According to ESPN Stats and Information at the time, Jackson faced 24 secondary blitzes, which was the highest number of blitzes involving corners and safeties in nearly a decade. Watching the game back now is still fairly stunning. Jackson, who, by the culmination of this season could end up being a three-time MVP, was visibly frustrated on the sideline. The Ravens shifted into nearly every typical counter that tends to fare well against Cover Zero, but the game plan had safety nets built in that allowed Miami to stay in the look but defend plays like a screen pass. 

“He’s innovative in thought,” Tomlin says. “He’s pliable. The talent he has at his disposal he can utilize.”

After that game, then Dolphins safety Jevon Holland said: “That was the most fun I’ve ever had.” 

Against the Packers in Week 4 of this season, the Vikings came out in this same look during Green Bay’s first third-and-long, which ended up forcing the Packers into a false start. On the next play they started in Cover Zero and as Jordan Love worked his way through his presnap checklist and audibled, likely to a play that increased protection and adjusted routes, the Vikings slowly walked their way back to a single-high safety look. 

Comparing those two Packers matchups in 2024, against one of the league’s best offenses, offers a small window into just how maddening a Flores defense can be and how it continues to evolve over time. For example, in the Week 17 matchup, the Packers found themselves in a second or third down with more than seven yards to gain 17 times. On just two of those plays, the Vikings were motionless at the line of scrimmage, meaning they remained in the exact look they presented when Love broke the huddle (and on one of those two snaps, Minnesota logged a sack while on another they ran a variation of my favorite presnap look in which the only two down linemen are defensive ends and there are no interior tackles with their hands in the dirt). On literally every other down, the Vikings faked a blitz, blitzed, shifted gaps for their defensive linemen right before the snap, feigned dropping someone into coverage before blitzing or actually dropped someone into coverage. In Week 4, the ethos was similar, but the looks were different; a jumbled mess of flying bodies that resembled an active beehive. 

While this is far too simplistic of a summation, this flurry of activity seems to consistently force a quarterback to take a little more time to diagnose what is happening and, because of this, he is left with lower-percentage throws to choose from. (Indeed, Love, who averages about 2.8 yards per dropback, took more than 3 seconds per throw in his first matchup against Flores this year.) Another reason why the Packers are an excellent case study here? With Malik Willis as their quarterback, they were better than almost any team in the NFL in generating easier mid-range completions despite the fact that all of their opponents knew this is precisely what they wanted to do. 

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The Vikings have swarmed opposing quarterbacks all season. | Steve Roberts-Imagn Images

A few years back I embarked on a fruitless quest to answer a nagging question I had about presnap motion. At the time, some defensive coordinators, bushwhacked already by mounting injuries, an imbalanced rulebook and the general sense that the NFL would rather them not exist so as to improve scoring, were resigned to the fact that offenses could do all of this fun window dressing while defenses had to remain somewhat static so as not to jumble their accounting of every offensive player. 

However, some offensive coaches were dialing back on presnap motion because of the way defenses reacted, which would then complicate their ideal reads. My curiosity: Why doesn’t a defense exist purely as an agent of chaos and, like offenses did to them for so long, throw optical curveballs on every snap? Why don’t they fight back?

While the keys behind Minnesota’s defense are myriad—perfectly suited personnel, sound tacklers, heady players with the ability to make calls on the field—Flores seems to have concocted the closest thing to, say, Mike McDaniel’s offense on defense. It’s mentally exhausting to digest. It’s like a jack-in-the-box that eventually pops, revealing a chainsaw-wielding madman.  

During Flores’s 2023 introductory press conference in Minnesota, he checked most of the boxes on the defensive coordinator platitude bingo card. He wanted his players to be tough and physical and sound when it came to their assignments. But he also mentioned that he wanted to see joy, and not just in the subtle, inside-joke kind of way two people in the same business might share a laugh, but actual, visible joy. That can only come from doing something truly different. 

After Flores graduated from his year of Patriots offensive graduate training, he asked to be moved over to the defensive side of the ball, and O’Brien was tasked with plucking the next poor soul to face the rigors of the red pen. It was clear that, after understanding what made the best offenses in the world happy, Flores had started to formulate a way to derive his own pleasure from making them miserable. 

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This article was originally published on www.si.com as Vikings DC Brian Flores Has Crafted a Defense That Fights Back.