Take a deep breath: there’s no reason to panic about the Chiefs’ defense

The statistics are scary. But looking at them in the right context — and remembering some history — can calm us down.

After the Kansas City Chiefs lost a close game for the first time in 679 days — giving up the second-most points in a contested game since defensive coordinator Steve Spagnuolo’s arrival in 2019 — many observers have concluded the team’s defense is truly bad.

There’s no doubt that against the run, the Chiefs’ defense has been a sieve through the first two games, giving up 404 yards on 67 attempts. That’s 6.0 yards per attempt, which ranks last in the league. They also rank dead last in net yards per passing attempt at 9.4 — and also in yards per play at 7.6.

So when someone says, “The Chiefs are the league’s worst against both the run and the pass,” they’re not wrong. But they’re not exactly right, either. Let’s examine these statistics in the proper context.

Run defense

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It’s difficult to find many rays of sunshine in the team’s performance against the run — except for one thing: their opponents in the first two games. Last season, the Baltimore Ravens led the league by averaging 5.9 yards per attempt. The Cleveland Browns were fourth with 5.2.

Knowing that Kansas City was going to begin the season against these two teams, it would have been entirely reasonable to expect that after just two games, they’d rank somewhere near the bottom in rushing yards — which is absolutely not to say the Chiefs had no responsibility to stop those teams on the ground. Instead, it’s to recognize that both of Kansas City’s first two opponents are outstanding at running the ball.

Pass defense

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While the team is last (or close to last) in both passing yards per attempt (Y/A) and net passing yards per attempt (NY/A), there’s a reason for that. The latter statistic adjusts Y/A by removing the yardage lost through sacks — and so far, the Kansas City defense has accumulated only three.

But another passing yardage statistic — adjusted net passing yards per attempt (ANY/A) — also adjusts for defensive interceptions. Kansas City’s ANY/A stands at 7.4 — which ranks 23rd. Obviously, that’s not a great number — but it isn’t dead last, either.

In fact, the Chiefs have been intercepting passes quite often — 5.3% of the passes attempted against them — which ranks as second-best behind the New England Patriots. In addition, their percentage of touchdown passes allowed is quite low. At 1.7%, it’s the league’s sixth-best figure. Since both of those percentages figure prominently in the way passer rating is calculated, Kansas City’s opponent passer rating is pretty darned good. At 88.5, it’s the league’s tenth-best mark.

I know this sounds like a lot of statistical magic tricks to pretend that allowing more passing yards than any other team isn’t a problem. But passer rating isn’t a magic trick.

Unlike many other statistics, passer rating has predictive value; by itself, it does a pretty good job of predicting whether a team will win or lose a game. In 2020, the NFL team finishing each matchup with a better passer rating than their opponent won 210 of the 255 non-tie games. In a 17-game season, that’s the same as 14 wins — which would likely be enough to easily win any of the NFL’s eight divisions in 2021.

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It probably wouldn’t surprise you to learn that the greater the difference in passer rating, the more likely a team is to win. In the 2020 games where one team had a passer rating at least 20 points greater than their opponent, those teams went 141-12. (Over a 17-game season, that’s 15.7 wins). Teams that went at least 30 points above their opponents went 107-8, while those going at least 40 points above were 74-3. And in games where the difference was at least 50 points, teams went 47-0! (The Chiefs, by the way, were the victors in four of those 47 games).

Over Patrick Mahomes’ 48 regular-season games since becoming the starter, his passer rating is 109.5. In that same period, the Chiefs’ defense has allowed a passer rating of 87.8. That’s a difference of 21.7 points. In his two 2021 games, Mahomes’ rating of 131.4 has been 42.9 points above those of the opposing quarterbacks.

I think you can do the math on that.

The bottom line

After Kansas City’s Week 2 loss to the Ravens, I pointed out that since Mahomes became the team’s starting quarterback, the team stands 21-2 in all games where opponents have gained at least five yards per rushing attempt. Before the team was defeated in Baltimore, the only other such game was the 35-32 regular-season road loss to the Tennessee Titans in 2019.

So the idea that the team’s poor run defense is a problem that will somehow prevent the team from a winning season is demonstrably false; running the ball “down the Chiefs’ throat” is not a “blueprint to defeat them.” Since Mahomes arrived, multiple teams have tried to beat Kansas City in exactly that way — and they have consistently failed. Mahomes (along with a competent pass defense) is the ace that will beat any face card that a strong rushing attack will provide.

Could it be a problem in an individual game — especially in the postseason? It certainly could. The losses against Baltimore last Sunday — and Tennessee in 2019 — show us that the team absolutely needs to improve its run defense. In both of those games, even a marginally better defensive performance against the run would have kept the Chiefs from even finding themselves in the unusual fourth-quarter circumstances that ultimately decided both games — and in the case of Sunday’s game, might even have given Mahomes another chance to win at the end.

It all adds up to this: there’s plenty of reason to be concerned about the Kansas City defense. There are problems that need to be solved — particularly the red-zone defense, which is a huge problem — and players who need to improve. There might even be some who need to be replaced.

But there is no reason to panic over it.