Last year, the Kansas City Chiefs had the league’s best offense but the team was undone by a defense that couldn’t get a stop. That led to an overhaul of the Kansas City defensive structure. Defensive coordinator Bob Sutton was replaced by Steve Spagnuolo and a number of additions were made on that side of the ball. Frank Clark and Alex Okafor were brought in on the edge. Bashaud Breeland and Tyrann Mathieu were added to the secondary in free agency and safety Juan Thornhill was selected in the second round of the draft.

Those moves completely reshaped the Chiefs’ defense and the results on the field have followed. The 2018 Chiefs were 26th in DVOA. That came with a wide split between the pass defense (12th) and a league-worst run defense by a mile (the gap between Kansas City and the next-worst run defense was about the same between that team and the one ranked 21st).

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This season’s Chiefs have still struggled to stop the run (30th) but the small improvement there and a huge leap in pass defense (sixth) has placed the defense 10th overall by DVOA. They’ve also done this while forcing turnovers at a lower rate than they did last season — 14.9% (fifth-highest) to 12.9% (11th). It’s been the huge leap in the down-to-down consistency of the pass defense, especially coverage, that has opened everything else up for this defense.

better corner play

The group of Breeland, Charvarious Ward, Kendall Fuller, and Morris Claiborne have been able to keep opposing offenses from going off. No one of this group would be considered “shutdown” but they’ve all given above-average performances in coverage this season. For the Chiefs, that’s a huge improvement.

Per Sports Info Solutions, 139 cornerbacks have played at least 100 coverage snaps this season. The Chiefs are one of three teams (along with the Baltimore Ravens and San Francisco 49ers) to have four cornerbacks in the top 60 of Adjusted Yards (yards weighted by touchdowns and interceptions) allowed per coverage snap. The average of the full group is 1.04.

Lately, especially in the last game against the Chicago Bears, Fuller has played some snaps at safety, but even when he was strictly playing nickel earlier in the season, teams were staying away from throwing into his coverage.

Kansas City’s corners have been able to both have play-to-play consistency while limiting big plays. Per SIS, just 44% of opposing pass plays have resulted in positive Expected Points Added this season, which ranks eighth. Last season, that was 48%, which ranked 17th.

The 2018 Chiefs allowed the most passing plays of 20 or more yards against them with 65. This season, the Chiefs are tied for the ninth-fewest allowed with 44.

Safeties to count on

Kansas City’s competence at cornerback has allowed the Chiefs to be more aggressive with their safeties, both in coverage and rushing the passer.

Spagnuolo has used pre-snap disguises to confuse opposing quarterbacks and he’s put a lot of trust in the players to get into the correct look at the snap. That’s easier said than done and the Kansas City secondary has been able to pull that feat off this season.

Late against the Bears in Week 16, the Chiefs showed pressure on a 1st and 10. Seven Kansas City defenders were up by the line with Mathieu close by in the slot and Thornhill as the single-high safety. But at the snap, Thornhill moved to the left and Mathieu dropped back deep. Meanwhile Fuller (29) had also dropped to the middle of the field. Fuller got underneath a post route to Javon Wims with Mathieu over the top. The throw was high over Fuller and almost ended as an interception for Mathieu.

 

Communication has also been key for this secondary. Against the Oakland Raiders in Week 13, the Chiefs had a two-high look against a trips bunch to the defense’s left from the Raiders. Before the snap, Thornhill and Breeland (21) can be seen discussing responsibilities. When Tyrell Williams took his route inside, Thornhill broke on the ball for a pick-6.

 

Mathieu had an impressive pick of his own earlier in the game when he broke off a deep route and uncut an out.

Send ‘Em All

As good as the Kansas City safeties have been in coverage, they’ve been used often as pass rushers. With the New York Giants, Spagnuolo often relied on getting pressure with the front four and dropping the rest of the defense into coverage. The Chiefs haven’t gone blitz crazy — they’re 13th in blitz rate (29.9%) per pro-football-reference, a leap from the 20.9% rate last season — but they have gotten the safeties involved. Mathieu is sixth among safeties in pass rush snaps, per SIS charting, and Daniel Sorenson is 12th.

Kansas City has combined all of this together when they run Cover 0, an all-out blitz with no deep safeties. The Chiefs have used a 0-blitz on 43 snaps this season, which is second only to the Ravens, who blitz on over half of their defensive drop backs overall. Last year, the Chiefs only used Cover 0 on 23 snaps.

On the all-out blitz, the Chiefs have found success with a high pressure rate and a low positive play rate allowed. They also lead the league in EPA per drop back on those plays.

Cover-0 Plays, 2019

TeamDrop BacksPressure RateComp%YPAEPA/PlayPositive Play %
Chiefs4351.1%30.9%4.2-0.5423%
League Avg.1645%49%5.20.0143%

The Chiefs have also been able to disguise this coverage, often giving a single-high look before that safety drops down into man coverage behind the blitz. Kansas City used this strategy to attack Tom Brady and the New England Patriots in Week 13. The Chiefs used a 0-blitz seven times against Brady, who went 1-of-7 for seven yards against it. 

 

Playoff Outlook

Some might be down on Kansas City because the offense isn’t as high-powered as it was last season. But the offense does still rank third in DVOA (with the second-best passing offense) and second in points per drive. Meanwhile, the improvement on defense has just about made up for the difference.

Last season’s Chiefs had a DVOA of 32.9%, which means they were about 33% better than an average team. This year, they’re at 29.5%., which is third but would have ranked first in 2018.

Unfortunately for the Chiefs, the two teams ahead of them in DVOA are both in the AFC. But Kansas City is getting healthier as a team and has shown multiple ways to win games this season instead of the one (albeit incredibly good) formula they had last season. The Chiefs might not be a Super Bowl favorite, but this team is deeper and more balanced than last season and that is going to give them a chance to make up for what they missed out on in 2018.