EDEN PRAIRIE, Minn. -- Mike Zimmer waited 35 years to get an NFL head-coaching job. The benefit of those preceding decades? When the Minnesota Vikings hired him in 2014, Zimmer knew the specific athletic profile he needed at each position to build a group that would cement his legacy as a defensive savant.

Four seasons later, the Vikings have the NFL's top defense -- whether you measure by scoring (15.8 points allowed per game), yards (275.9 per game) or third-down percentage (25.2). No Minnesota defense has accomplished that feat since 1970, and it can be attributed in large part to a roster that includes two All-Pros and two players who made the Pro Bowl.

"Without giving away all my secrets," Zimmer said, "I like a certain body type with guys. You can kind of look at most of them and tell what we're trying to get: athleticism, guys who can think quickly on their feet, safeties that have versatility, corners who can cover."

The amateur account of Zimmer's personnel profile goes something like this: tall cornerbacks, athletically versatile safeties, long pass-rushers and fast linebackers. As we'll see, general manager Rick Spielman pursued similar players both before and after hiring Zimmer, far exceeding draft norms while also utilizing free agency as an important supplement. Spielman had two "Zimmer players" on board in 2014: Safety Harrison Smith, a first-round pick in 2012, and cornerback Xavier Rhodes, selected in the 2013 first round. Smith can play anywhere -- in center field, in run support and on blitzes. Rhodes is 6-foot-1 and uses every inch of his size to suffocate receivers in man defense. Zimmer cherishes tall cornerbacks so much, in fact, that he pushed Spielman to draft another in the first round of the 2015 draft: 6-foot Trae Waynes.

"When you don't have to worry too much about the corners," Zimmer said after drafting Waynes in 2015, "you don't have to give them much help. You don't have to cheat the coverages. You can do numerous things that allow you to attack offenses. But when you have to help a guy or protect a guy, use some more of your guys than you really would like to, then it makes it more difficult." NFC divisional round: Saints at Vikings New Orleans (11-5) at Minnesota (13-3), Sunday, 4:40 p.m. ET, Fox • Saints, Vikings changed since Week 1

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Defensive end Everson Griffen, Zimmer's third inherited starter, did not fit the profile. At 6-foot-3 with 32⅝-inch arms, he was shorter and stouter than the type of player who typically succeeds as an outside pass-rusher. In Griffen's case, however, exceptional quickness and motor have helped him amass 43.5 sacks since Zimmer installed him as a starter after arriving in 2014, the fourth most in the NFL over that span.

But if you want to see a Zimmer defensive end, look on the other side of the defensive line. That's where you'll find the 6-foot-5 Danielle Hunter, who has 34¼-inch arms. Hunter, who had 1.5 sacks at LSU in 2015 before Spielman made him a third-round draft pick, has 19.5 sacks over the past two seasons.

Zimmer's primary linebackers are Anthony Barr, a first-round pick in 2014, and Eric Kendricks, a second-rounder in 2015. At the NFL scouting combine, they ran the 40-yard dash in 4.66 and 4.61 seconds, respectively.

In all, Spielman built this defense with focus and intent. Research by ESPN senior statistics analyst Jacob Nitzberg shows that the Vikings have been among the NFL leaders in drafting defensive players, both in volume and quality, since selecting Smith in 2012.

Let's put Spielman's approach in better context by contrasting it with the rest of the league:

Volume

The Vikings have selected 17 players in the first three rounds dating back to that 2012 draft. Of that group, 10 were defensive players -- tied for the 11th most in the NFL during that period. By percentage of defensive players taken in the first three rounds since 2012, the Vikings rank No. 10 (58.8 percent).

Why is volume important? No matter how clear-minded a coach is about the type of player he wants, or how skilled the general manager is in identifying potential stars, no team can expect to hit on them all. The Vikings have had some disappointments -- including 2013 first-round pick Sharrif Floyd, a defensive tackle whose career might be over because of a knee injury -- but were able to overcome them with multiple swings of the bat.

Minnesota's overhaul on defense began with the hiring of Mike Zimmer in 2014. Adam Bettcher/Getty Images

Quality

Those 10 picks have delivered Smith, Rhodes, Waynes, Barr, Kendricks and Hunter -- in other words, the heart of the Vikings' defense. (Griffen was a Spielman pick in 2010, but didn't become a starter until Zimmer arrived.)

To judge quality relative to the rest of the NFL, Nitzberg used the weighted career approximate value metric (CarAV) at Pro-Football-Reference.com, detailed in the chart at the bottom. In short, approximate value sweeps up player performance at various positions into a single number for comparison purposes. CarAV weights those numbers toward the best season of a player's career to document his performance ceiling. The Vikings' 10 picks in the first three rounds since 2012 have a CarAV of 18.6 per player -- tied for third highest in the league during that period. That's a numerical way of demonstrating that the Vikings have been much better than most of the NFL at drafting and developing high-level defensive players in the rounds that generally deliver them.

Financial maneuvering

In the bigger picture, the Vikings have not limited themselves to developing their roster with draft picks. In fact, they used picks in the first three rounds on only six of the 12 defensive players who were on the field for at least 500 snaps this season. Six NFL teams had more. Why is that? In part it's because three of their starters were acquired via free agency. Defensive tackles Linval Joseph and Tom Johnson both signed in 2014, Johnson initially acquired as a backup for Floyd. Safety Andrew Sendejo, meanwhile, was signed in 2011 after the New York Jets released him from their practice squad.

The Vikings changed their financial philosophy to retain this nucleus. Joseph, Rhodes and Griffen signed contract extensions last summer, locking them up through 2022. Smith is signed through 2021. Barr, Kendricks and Hunter could sign new deals as soon as this spring.

None of it would have mattered in 2017, of course, were it not for the team's extraordinarily fortunate health. While their offense has gone through transitions at quarterback, running back and multiple positions on the offensive line, the defense has lost only three starts for injury all season. Sendejo missed two games with a groin injury (and was suspended for a third), while Griffen sat out one game to rest plantar fasciitis in his foot.

As a result, Minnesota's depth has not been tested nearly as much as other teams' have. What you have seen in 2017 is largely the execution of the team's best-case scenario -- the players they identified for key roles have filled them exceptionally and nearly without fail, which is why the defense makes the Vikings among the favorites to win Super Bowl LII.