Let’s start with something you already know.
in 2018, the Kansas City Chiefs defense was ranked 31st in the NFL. That’s the number that national media voices — and many local ones, too — have been throwing out when discussing the Chiefs defense ever since the closing weeks of the 2018 season.
If you’re going to make your judgment about the 2018 Chiefs defense strictly based on of the number of yards they allowed, that’s the right number to use. The Chiefs allowed 6,488 yards last season, which was indeed 31st in the NFL.
But thanks to the hyperbole machine of the modern media — much of which is immune to any kind of thoughtful analysis — reliance on that number has allowed another idea to take root: every facet of the Chiefs defense was terrible in 2018. The inevitable extension of this concept is that every personnel group in the defense now needs to be completely revamped.
But if we look more deeply at the numbers, we find this isn’t necessarily true.
It’s likely you already know that with Dee Ford, Chris Jones and Justin Houston, the pass rush was one of the few bright spots on the Chiefs defense in 2018. The unit tied the Pittsburgh Steelers with 52 sacks on the season, which was good for first in the league.
But like so many other volume stats, that figure can be misleading. The Chiefs ranked only eighth in sack percentage — that is, the number of sacks divided by the number of passing attempts — at 7.6%. This is because the Chiefs faced 632 pass attempts in 2018 — more than any other team in the league.
So while the Chiefs racked up the most sacks, they weren’t the most effective team at getting them; the large number of sacks the Chiefs collected actually said more about the plays their opponents ran than it did about the Chiefs’ ability to get to the quarterback.
You can probably already guess why this was the case: with the Chiefs’ high-flying offense behind Patrick Mahomes, the Chiefs scored early, fast and often. Opponents were frequently playing from behind — which naturally led to more passing attempts.
And that led to more passing yards — another volume stat that tells a misleading picture of the Chiefs defense.
The Chiefs allowed 4,374 yards passing in 2018 — 31st in the NFL. Without looking more deeply, someone might easily conclude that the Chiefs secondary was awful. Many fans (and media members) have apparently done just that and reached that conclusion.
But the deeper numbers say it wasn’t awful.
Even using the traditional (if somewhat flawed) passer rating statistic, you can see this was true. In 2018, the Chiefs defense allowed a passer rating of 92.7 — tied with the Houston Texans for 12th in the league.
That’s right: 12th. Not great. Not even good. But solid. And way better than 31st.
If your quarterback is Mahomes — whose passer rating was 111.7 in 2018 — that 92.7 opponent passer rating will win you a lot of games. Whatever problems the passer rating statistic may possess — and it has quite a few of them — it does correlate pretty well with winning games. A 19-point differential between your quarterback and your opponent’s will definitely indicate wins are likely — maybe even quite a few of them.
Looking at other passing statistics leads to similar conclusions.
For the three primary passing yardage statistics — yards per attempt, net yards per passing attempt and adjusted net yards per passing attempt — the Chiefs came in at 7.5 (16th), 6.4 (12th) and 6.3 (12th) respectively.
Football Outsiders — whose top-level DVOA statistic ranked the Chiefs defense 26th instead of 31st — rated the Chiefs pass defense at 4.7%. That’s a bit below average — negative numbers are better than positive ones — and that figure was 12th-best in the league.
But what’s even more interesting is what you see when you look at how FO rated the Chiefs passing defense against different types of pass receivers.
DVOA Against Receiver Type
|vs. WR1||vs. WR2||vs. WR3+||vs. TE||vs. RB|
|-9.2% (9)||-23.8% (5)||21.6% (29)||19.1% (25)||7.3% (21)|
What this shows is that against first- and second-tier wideouts, the Chiefs actually did very well in 2018 — ranking ninth and fifth against them — but poorly against other types of receivers.
This means that in 2018, Chiefs cornerbacks tended to play pretty damn well — certainly better than most people realize — and against the pass, Chiefs safeties and linebackers tended to play poorly.
I’m not going to go through the numbers on run defense. The volume stats are awful, and so are the numbers that provide more context to them. The 2018 Chiefs run defense was just... bad.
But with this information in hand, the moves the Chiefs have made in free agency and the draft may come a little more clearly into focus. Moving on from Ford and Houston was probably mostly about creating salary cap space and acquiring players better suited to Spagnuolo’s 4-3 Under scheme — players like Frank Clark, Emmanuel Ogbah and Alex Okafor. In total, these moves should bolster the run defense without a significant drop-off in pass rushing.
Eric Berry’s release also freed up space, and created a roster spot for Tyrann Mathieu — a player who is much like Berry was in his prime: a multifaceted safety who can cover and also provide run support. If Veach selected well with Juan Thornhill — which early indications say he did — the Chiefs should have a solid player to pair with Mathieu. But if not, they’ll have Jordan Lucas, Armani Watts and Daniel Sorensen from whom to choose.
Since the Chiefs haven’t made big moves at linebacker, you could conclude the team is satisfied with the linebacker corps as it stands for the 4-3 scheme — or that another move might be yet to come.
But the relative lack of inactivity at cornerback might now make more sense than it did when you started reading this article.
In essence, the Chiefs have replaced Steven Nelson with Bashaud Breeland at cornerback. They could conceivably stand pat with Kendall Fuller and Breeland as starters without seeing a significant drop-off in coverage — especially with the Honey Badger now on the field — and still have players like Charvarius Ward, Keith Reaser or Rashad Fenton backing them up.
We can’t say with certainty that the Chiefs aren’t planning a big move to acquire another player in the secondary; one thing we’ve learned about Brett Veach is that he is unpredictable.
But what the data shows is that the defensive secondary might be in better shape than we have imagined — or at the very least, the Chiefs may see it as the part of the defense that doesn’t need further attention.
The Chiefs could do nothing, and be just fine.