Our 2020 Defense

How the Vikings improved their cornerback room — and why it was an issue in the first place — is likely a continuing story, but it starts with the ability to hold back a Seattle offense that was surprisingly anemic on Sunday.

If the Vikings are the playoff team that they seem to think they are, the ability to hold back high-octane offenses will be part of the argument, and being in one-point games against two still-undefeated teams (Seattle and the Tennessee Titans) is fairly telling. After all, once one accounts for strength of schedule, the Vikings might be the 11th “best” team in the league.

If they for the most part shut down the Seahawks, it might be the direction the defense takes going forward. Two years ago, their failure in back-to-back games against the Bills and Rams led to a change in coverage shells as they moved from a primarily Cover-3 defense to a Cover-4 (often called “quarters”) defense. That significantly improved their defense and it turns out that this put them at the forefront of a coverage revolution, allowing them to avoid the strategies offenses had developed to counter the popular Cover-3.

The number in “Cover-X” typically refers to the number of players in deep zones at the back end of the defense, though not always. Cover-6, for example, refers to a coverage shell that is played like Cover-4 on one side and Cover-2 on the other. Cover-7 refers to a coverage with two-deep safeties but has a number of complex rules assigned to it that change based on what the offense is doing. Tampa-2 is a Cover-2 shell with a middle linebacker also taking a deep assignment between the safeties. The basic coverages are below.





I tracked every coverage shell the Vikings used over the past five games to see what has worked for the Vikings and what hasn’t — and whether there’s been a change in their approach. It turns out, they’ve changed things again, and it may be a reason they’ve become a bit more successful in pass defense over the past few weeks.

The Vikings base defense seems to be returning to what it was before head coach Mike Zimmer arrived — Cover-2. The Vikings used to run variations of the defense under previous coordinators, namely Leslie Frazier, and the Tampa-2 variation was popular in Minnesota as well as a number of defenses throughout the 2000s. That memory might not make people happy, but football is fairly cyclical.

In fact, Seattle’s Cover-3 is a tweak from the Tampa-2 that Pete Carroll learned under Monte Kiffin, who ran the Tampa-2 defense for Tampa Bay’s remarkable 2002 squad.

Through the 2018 and 2019 seasons, the Vikings played more Cover-4 than any other team, with Sports Info Solutions identifying 14.5 percent of early-down defensive plays (in two-score situations) utilizing the scheme. They also played a nearly even amount of Cover-3 at 14.8 percent and a good amount of Cover-1 at 21.9 percent. There’s a chance that they played more Cover-3 than Cover-1 despite this data, however, because they can look very similar against teams who go vertical, especially in Zimmer’s scheme, where corners often use man coverage techniques in zone.

The Vikings used more Cover-4 and less Cover-3 in 2019, leading the league in the look with 25 percent of their early-down, within-two-score coverages coming from Cover-4. They didn’t eschew Cover-2 in that time, though, using it on 20.5 percent of snaps. Moreover, their third-down blitz looks often used Cover-4, so they leaned on the four-deep coverage quite a bit.

The past two weeks, however, the Vikings have switched to Cover-2 coverages much more often. Some variation of Cover-2 was run on 40 percent of early-down snaps within two scores against the Texans and Seahawks.

The idea behind this might be to limit explosive plays. Previous iterations of the Vikings did well enough to limit big plays — they ranked 13th in sideline deep-catch rate between 2018 and 2019 but currently rank third in 2020, per SIS. Because Cover-4, Cover-3 and Cover-1 ask corners to handle deep routes themselves, there’s not much protection if things go wrong.

In Cover-2, however, corners will either avoid going deep or will have help when they do have cause to follow downfield. Of course, Zimmer has made his thoughts on the relative ease of playing Cover-2 well known.



Aside from the fact that it provides some schematic help in dealing with deep routes, it also asks the best players to do the most important job. Anthony Harris and Harrison Smith are simply better players than the cornerback group and having them shut down deep balls makes sense.

The Vikings have made tweaks to the traditional Cover-2 in order to avoid some of its traditional weaknesses. Many times, the safeties will line up within eight yards of the line of scrimmage and sprint to their landmarks after the snap, which allows them to be active in the run game.

Typically, two high safeties in Cover-4 and Cover-2 makes it difficult to defend the run when compared to single-high orientations. Taking a player out of the box generally encourages the other team to audible out of the pass into the run. That’s one reason that Cover-2 is a go-to two-minute-drill coverage — because offenses don’t want to run in that situation.

It’s also one reason the Seahawks, the most pass-happy team in the league, decided to run so much against the Vikings. In a game where they were largely playing from behind, they ran the ball 15 times and threw it 20 times before the final drive. While the final rushing numbers look damning (124 yards on 16 carries), the three biggest runs were from the quarterback. When evaluating it from a success rate standpoint, the Vikings defense against running backs was 55 percent.

Given that the Seahawks earned substantially more in terms of yardage and expected points when they dropped back to pass, it was a good idea for the Vikings to funnel them into the run game. Not only that, the Seahawks only completed one pass over 20 yards in the air, and that occurred on the final drive.

The Cover-2 (and Tampa-2) fell out of vogue for good reason in the NFL. Teams passing out of three-receiver sets found it easy to exploit the holes in the coverage, either by sending all three receivers deep, therefore flooding the safety zones, or by using route combinations on one side that exploited the look — the smash concept, the sail concept, divide and mills. Not only that, fast tight ends exploited the seam between the two safeties and became increasingly difficult to defend.

The Vikings have thus far not seen too many of these plays in Cover-2, but they are mixing things up enough that these might not be a huge issue. Many of their Cover-2 snaps come in man coverage, not zone, and therefore aren’t susceptible to attacks specifically on the seams. They will also mix in Tampa-2 with their Cover-2 looks, which not only helps take care of those tight ends with the athletic linebackers the Vikings have, but allows the safeties to squeeze the sidelines better on deep routes. That gives them more opportunities against sail and smash.

There’s some chance that allowing the safeties to consistently hawk from behind the box could lead to more turnovers. Harris is no stranger to picks coming off of Cover-2, after all.



But that might come at the cost of turnovers at the second level. While zone coverage purportedly leads to more pick opportunities because eyes are focused on the quarterback rather than the receiver, Cover-2 principles often eschew interceptions. Playing for punts instead of picks is something that Zimmer is used to, however. They’ve fielded top-level defenses without topping the charts in turnover rates and they might have to do so again.

Cover-2 also allows the Vikings to implement unique blitz packages. An ardent proponent of “safe pressure”, Zimmer has thus far shown the capability to showcase two-high safety looks that turn into blitzes, which isn’t common around the league.



While most of these blitzes are based on Cover-4 concepts — again, fairly unique — the ability to show split safeties before the snap and then blitzing a linebacker while keeping the deep pass under check is not something many teams are capable of.

This isn’t a magic panacea, but the Vikings will likely be floating around above-average territory if these schematic changes consistently allow them to stay ahead of opposing offenses. That should be enough for a slowly cohering offense to pull together some wins. If the Vikings can play like a .600-level team the rest of the way, they’ll win six or seven games and potentially sneak into the seven-team playoff picture at 8-8. Given that the schedule gets easier from here, a few lucky bounces of the ball with an improved defense and explosive offense could salvage the season.