Stopping the run is still important for defenses if they're going to succeed, but the modern NFL asks more of its defenders. They now need to stop the run, pressure the quarterback and take away opportunities to complete passes once the ball is in the air.
We've already covered the pass-rushing element of this pursuit with our top disruptors entry in the Next Gen Stats series. Now we're taking a look at the players on the back end of the defense.
Now, here are some important notes about the parameters I used to separate the best coverage defenders from the rest. In order to qualify, players needed a minimum of 300 coverage snaps, 40 targets as the nearest defender and a catch rate allowed below expectation (meaning they're consistently breaking up passes that were likely to be completions). Also, qualifiers needed a negative targeted expected points added (a metric used to quantify how much an individual player impacts an opponents' scoring potential and the most important metric used in this exercise), a tight-window percentage of at least 20 (15 for linebackers, due to the nature of their position as second-level run defenders and coverage defenders) and a maximum passer rating allowed of 80.
One notable player who did not make the top 10: Dallas Cowboys standout Trevon Diggs. His performance has already attracted plenty of debate, as not everyone sees him as a true blanket corner. He certainly uses his excellent closing speed and ball skills to make plays on passes. That showed in his passer rating allowed (60.9), ballhawk rate (24.4 percent) and targeted expected points added (-23.3, the fourth-best mark in the NFL). The latter two metrics were heavily impacted by his ability to force turnovers (posted a league-best 11 interceptions).
But Diggs isn't on this list because he failed to meet the tight-window percentage requirement (Diggs' rate was 16.3%; needed at least 20% to qualify). This exercise is designed to identify players who make it as difficult as possible for opposing quarterbacks to fit passes into their coverage, and Diggs just doesn't do that at the rate of the defenders listed here.
Unlike last year's rankings, no linebackers made the cut, further emphasizing just how impressive Fred Warner's coverage was in 2020. It's tough to crack these rankings at that position.
With that out of the way, let's explore Next Gen Stats' top coverage players of 2021.
JUST MISSED THE CUT: Kyle Dugger, S, New England Patriots; Darius Slay, CB, Philadelphia Eagles; Carlton Davis, CB, Tampa Bay Buccaneers.
Passer rating allowed: 73.1
Catch rate allowed below expectation: -9.5%
Tight window pct: 22.2%
Target rate: 15.8%
Average separation: 2.6 yards
Targeted expected points added: -10.5
Howard began the 2021 season on the heels of contract-related drama that seemed to bleed into the on-field action. In Weeks 1 through 8, Howard allowed a passer rating that flirted with 100, gave up five touchdowns as the nearest defender in coverage and posted a targeted EPA of +11.8. Not great, Bob.
Then, Howard turned things around in remarkable fashion. In the following nine weeks, Howard allowed the second-lowest passer rating at 42.9 (min. 30 targets in that span) and the fifth-lowest targeted EPA (-19.4). He gave up just two more touchdowns as the nearest defender, bringing his targeted EPA back toward a level good enough for this list at -10.5. After all the money-related discourse, Howard signed a five-year extension in April.
Instead of being atop this list, as he was after the 2020 season, Howard rounds it out at No. 10. But if he continues his play from the second half of 2021 in 2022, he'll likely land higher in a year. With the money issue now solved, he can focus solely on producing at an elite level once again.
Passer rating allowed: 60.5
Catch rate allowed below expectation: -10.3%
Tight window pct: 21.2%
Target rate: 16.9%
Average separation: 2.6 yards
Targeted expected points added: -11.9
Dean would be a spot higher on this list if Levi Wallace had not outperformed him in targeted EPA. That's not much of a knock on Dean, whose NGS metrics jumped off the screen and screamed at me when compiling this list. Quarterbacks completed just 48.5 percent of passes in which Dean was the nearest defender, producing a coverage success rate (the percentage of targets that result in a successful play for the defense) rivaling that of A.J. Terrell, who, as you will see, is ranked very high on this list. And Dean allowed the ninth-lowest passer rating (60.5) in the league. Entering a contract year, Dean has certainly built positive momentum that could result in quite a pay day.
Passer rating allowed: 73.8
Catch rate allowed below expectation: -2.6%
Tight window pct: 27.2%
Target rate: 18%
Average separation: 2.4 yards
Targeted expected points added: -15.3
After earning a new deal with the Steelers in free agency, Wallace lands on this list for a few reasons. His targeted EPA is a strong -15.3, and his tight-window percentage of 27.2 is indicative of a corner who stays very close to the intended target and is ready to make a play. Wallace's 10 passes defensed should come as no surprise, then, and he might have landed higher on this list had he finished with more than two interceptions (on 81 targets). Wallace might not have racked up the gaudiest numbers, but he's frequently in the right position to make a play. He'll end up with a better ranking if he makes more of those plays in Pittsburgh.
Passer rating allowed: 74
Catch rate allowed below expectation: -7.4%
Tight window pct: 20.6%
Target rate: 19.6%
Average separation: 2.8 yards
Targeted expected points added: -18.2
Seeing Dantzler here might come as a surprise, but the metrics for him were too good to overlook. He posted a targeted EPA of -18.2 (10th among DBs). Dantzler excelled at limiting yards gained by opposing pass catchers, allowing just 4.9 yards per target in coverage, one of the lowest rates in the NFL. He also tied for the fourth-fewest yards after catch per reception allowed at 2.3. A tight-window percentage of 20.6 just barely nudged him into qualifying for the list, but it allowed for folks like me to realize Dantzler was better in coverage than most realized.
Passer rating allowed: 75.8
Catch rate allowed below expectation: -6.4%
Tight window pct: 28.2%
Target rate: 21.7%
Average separation: 2.6 yards
Targeted expected points added: -19
We always get a few surprises with these rankings, and Cowboys fans will likely raise an eyebrow at this one. (I know I did.) For much of 2021, it felt like Brown was getting attention for being on the wrong end of a completion, but his total résumé tells a different story. Brown saw more targets as the nearest defender than any other player in 2021 with 117, yet he was consistently right there to make a play -- or, at the very least, make a completion difficult. Despite the high volume of targets, Brown's tight-window rate was over 28 percent, and he allowed the sixth-lowest completion percentage among defensive backs (49.6). His completion percentage allowed below expectation finished at a solid -6.4 percent, and he finished with the sixth-lowest targeted EPA on deep balls (-6.8). While Trevon Diggs attracted the lion's share of positive praise in 2021, Brown was there on the other side playing a solid No. 2 cornerback.
Passer rating allowed: 62.7
Catch rate allowed below expectation: -8.6%
Tight window pct: 23.5%
Target rate: 9%
Average separation: 2.6 yards
Targeted expected points added: -21
Byard, the only safety on this list, finished with a ballhawk rate of 25.5 percent (best in the NFL, min. 50 targets) thanks to his five interceptions (tied for the most among safeties) and 13 passes defensed (most among safeties). He allowed a passer rating of 62.7, posted a completion percentage allowed under expectation of -8.6 percent, and put all of that together to record a targeted EPA of -21. He was especially effective at taking away perceived mismatches, finishing with the lowest passer rating allowed (min. 15 targets) when covering tight ends at 15.1. In these rankings, he's the best at his position.
Passer rating allowed: 59.9
Catch rate allowed below expectation: -6.1%
Tight window pct: 28.1%
Target rate: 20.6%
Average separation: 2.4 yards
Targeted expected points added: -21.8
There's no better time to show you're headed for a bright future than in your first season, and Surtain did just that in 2021. The rookie stepped right into the spotlight last season, recording an interception in his second professional game and snagging two picks against the division-rival Chargers in Week 12, taking one back for a touchdown. Such plays on the ball powered his targeted EPA, which landed at -21.8, sixth-lowest in the NFL and fourth-lowest on this list. Offenses that thought it wise to test the youngster soon learned that was a mistake. Surtain allowed a passer rating of 59.9 as the nearest defender -- and he was even better downfield, running with intended targets and taking away their chances to make a positive impact, posting the fourth-highest tight-window rate (62.5%) on deep targets (20-plus air yards) while finishing with the best targeted EPA on such throws at -16.9. He proved himself to be worth the first-round pick spent by the Broncos and is on a trajectory for even greater things in 2022 and beyond.
Passer rating allowed: 48.5
Catch rate allowed below expectation: -6.9%
Tight window pct: 29.2%
Target rate: 17.5%
Average separation: 2.3 yards
Targeted expected points added: -22.7
The story of Douglas' 2021 season should be printed and distributed to anyone who's ever run into adversity and wondered what to do next. Douglas was without a spot on an active roster, relegated to Arizona's practice squad at the start of the season, and it took a smattering of injuries in Green Bay to buy him another shot at playing time on an NFL field. Douglas didn't waste it, stepping into the Packers' secondary and quickly proving to be an essential part of the defense, recording five interceptions and 13 passes defensed (good for a ballhawk rate of 20 percent). His ability to make timely plays on the ball pushed his targeted EPA into the top three among defenders eligible for these rankings at -22.7, and a tight-window percentage north of 29 further emphasized his ability to shut down pass catchers in coverage. Instead of toiling away in the anonymity of a practice squad, Douglas ran with his opportunity in Green Bay and showed the NFL he could be a prime-time player for the NFC's top seed. The Packers saw this and knew they had to keep him, signing him to a three-year, $21 million contract in March. That's money well-earned.
Passer rating allowed: 48.4
Catch rate allowed below expectation: -8.9%
Tight window pct: 20.8%
Target rate: 21%
Average separation: 2.9 yards
Targeted expected points added: -27.1
Jackson has a new home in sunny Los Angeles, and he's bringing a premier résumé with him. Jackson finished second in targeted EPA (-27.1), recorded eight interceptions (boosting his ballhawk rate to 24 percent), allowed a passer rating of just 48.4 and posted a completion percentage allowed under expectation of -8.9 percent. The only statistical downside was his tight-window percentage, which just barely made the cut at 20.8 percent. Still, with 23 passes defensed on 96 targets (making him one of the most targeted players in the league), Jackson was consistently disrupting pass attempts. He proved he wasn't just the other corner playing opposite 2019 Defensive Player of the Year Stephon Gilmore in his first season without him, and the Chargers paid him accordingly.
Passer rating allowed: 49.9
Catch rate allowed below expectation: -14.6%
Tight window pct: 30.1%
Target rate: 14.8%
Average separation: 2.7 yards
Targeted expected points added: -29.4 (best in NFL)
The expectations for the Falcons might not be high entering 2022, but we should all make it a point to closely watch Terrell this season. While Atlanta fought to be a competitive team in 2021, Terrell blossomed in a significant way. He posted league-best marks in a number of categories, including completion percentage allowed (41.1 percent) and yards allowed per target (4.1). Terrell performed at an elite level in only his second professional season, boasting a coverage success rate (the percentage of targets that result in a successful play for the defense) of 68.5 percent (best among qualifiers). He has an incredibly bright future ahead of him.
Follow Nick Shook on Twitter.
