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Chiefs-Vikings: Stacking the Box Score for Week 9

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Stacking the Box Score is an advanced analytics perspective on the most-recent Chiefs game

NFL: NOV 03 Vikings at Chiefs Photo by Scott Winters/Icon Sportswire via Getty Images

Welcome to this week’s Stacking the Box Score, where I’ll be quantifying what went down between the Kansas City Chiefs and their most recent opponent — in this case, the Minnesota Vikings, whom the Chiefs defeated 26-23 on Sunday.

As always, here’s a quick primer on some of the stats and data I’ll be using. If you already feel comfortable with the advanced metrics, skip the link and keep reading!


Chiefs vs. Minnesota Vikings, November 3


Win probability

The win probability chart from this game looks very similar to the chart from the Chiefs-Lions game in Week 4. There are, however, a few unique plays worth pointing out.

First, this is the first Chiefs game this season with three plays that had a swing of 20% or more in win probability; the game was largely defined by a few big plays. The first was the Damien Williams touchdown run. This took the Chiefs from less than a 30% chance of winning to the same chance as a coin toss.

The next two biggest swings in win probability came in the final two drives of the game — both of them significantly boosting the Chiefs’ chance of winning.

After the Kansas City defense forced a punt by stonewalling the Vikings on their final drive, Britton Colquitt took the field to punt the ball away. While getting to fourth down was bad enough for the Vikings, the actual fourth-down play result was far worse: a 27-yard punt that immediately put the Chiefs in field goal range. As Pete Sweeney pointed out, this was more than just random misfortune; after the game, Colquitt admitted that he was focused on keeping the ball out of the Tyreek Hill’s hands.

On the next play, however, the Vikings defense sacked Chiefs quarterback Matt Moore, knocking Kansas City back out of range. Undeterred, Moore found Travis Kelce for 17 yards on second-and-21, bringing his team back into comfortable field goal range and largely sealing the game; the Chiefs’ win probability shot all the way up to around 90% after Kelce made the grab.

Quarterback performance

It’s not a Stacking the Box Score article without an evaluation of the quarterbacks who played.

Moore had a good game against the Vikings. While his EPA per dropback was only a bit over average relative to the rest of the league in 2019, he certainly did enough to win.

There’s been a consistent trend the past few weeks: on average, Moore hasn’t passed as deeply as Patrick Mahomes. That remained true in Week 9.

But we already know Mahomes throws deeper than most of the league. So how does Moore compare to the rest of the league?

While not a dramatic difference, Moore has thrown a slightly higher proportion of deep bombs (30-40 yards) than the league average. Other than that, he’s been on par with the rest of the league.

How well did he throw the ball — and how did he compare to Vikings quarterback Kirk Cousins? Let’s plot their EPA against their comletion percentage over expectation (CPOE).

Before we discuss Moore, look at how Cousins is far to the left on this chart. I don’t think any team in the league wants their quarterback to be on an island to with Mitchell Trubisky. Upon first look, it’s shocking that Cousins managed to put up a good EPA with such horrible accuracy.

But look what happens when we filter out third-down plays.

On first and second downs, Cousins was below the average in EPA.

What this shows is that Cousins was wildly inaccurate and inefficient on first and second down — which gave him a lot of third downs. Completing passes on down can significantly boost EPA — and in fact, all of three of Cousins’ touchdown passes were on third down.

Moore had just about an average week by EPA standards — but did very well when we look at his accuracy (left-to-right on the chart). This likely means that sacks — not his passing — are what dropped his EPA; sacks don’t factor in to CPOE. It’s very encouraging to see this accuracy — but with Moore taking a lot of sacks, we’re starting to see a trend.

While it’s only been two games, it’s interesting how many more hits and sacks Moore has taken compared to Mahomes. Since the personnel on the offensive line hasn’t changed much since Week 5, this is likely due to his decreased ability to scramble relative to Mahomes.

Receivers

Whether through scheme, good tackling or sub-optimal decision-making from Moore, Chiefs receivers had very little success after the catch on Sunday. The good news is that this isn’t likely to repeat itself, so the Chiefs could expect even more efficiency from Moore if he continues to sub in for Mahomes.

How efficient was each receiver with their targets — and how accurate was Moore when targeting them?

Demarcus Robinson continues to be inefficient, while Tyreek Hill was the complete opposite against the Vikings. Sammy Watkins and Travis Kelce were both positive on average — even if slightly below the league average for CPOE and EPA when targeted.

Rushing

Outside of Damien Williams’ 91-yard touchdown run, the Chiefs’ rushing attack didn’t have much to write home about. The run defense, on the other hand...

What this means is that Vikings running back Dalvin Cook was hit so frequently at (or behind) the line of scrimmage, all of his 71 yards rushing came after contact. This led to the the Chiefs being the third-best run defense by EPA in Week 9 — an incredibly impressive outing, considering Minnesota came in to this game ranked ninth overall in EPA per run.

Where did the Vikings find their limited success?

It couldn’t be more clear that running to the right side was the place the Vikings had the most success. This has now become a very clear trend, which is evident when we look at all rushes against the Chiefs so far.

With over 60 runs to both sides of the ball, there’s a large enough sample to draw some conclusions. Teams have not only been targeting the right side (from the offense’s perspective) more often, but they have been far more successful doing so.

It will be interesting to see if future opponents use this to their advantage better than the Vikings did; despite having more success to the right, they ran more often to the left.

Play-calling

When it comes to play calling, there were a lot of things the Chiefs did well on Sunday.

But there was also something they did very, very poorly.

On second-and-17 — with two-and-a-half minutes left in the half — the Chiefs punted the ball.

You may not remember it that way. Instead, you might remember a hand-off to Damien Williams that gained one yard.

But the Chiefs might as well have gone ahead and punted it.

First, let’s look at all passes and runs on second-and-long over the past decade, so we can see how often they led to eventual first downs or touchdowns.

Passing on second-and-long leads to a first down or a score between 40-60% of the time — while running it leads to success only 20-40% of the time — depending on how far back the line of scrimmage is. That means by running on second down, you’re decreasing your chances of continuing the drive (or scoring) by between 33 and 50%.

But these figures just show historical averages. Surely if the Chiefs continue to call a run in these situations, they must be good at them... right?

Well... no.

The mind-boggling part is the Chiefs have actually been far worse than league average on second-and-long runs during the past couple of seasons. Since the start of the 2018 season, the Chiefs have encountered 71 second downs with 10 or more yards to go. They’ve passed 55 times, converting 69% of those series. They’ve run the ball 16 times, converting just 13% of the time.

When we restrict it to second downs with more than 10 yards to go, they’ve converted... well, none of them. That’s right: running on second down with more than 10 yards to go has essentially been punting the ball away to the opponent. Sticking with the more favorable 13%, this still means that in these situations, the Chiefs have been almost six times as likely to continue their drives when they pass the ball.

Six. Times.

On the Chiefs’ final drive of the game they encountered an additional second-and-long scenario — this time a second-and-21. Whether Reid finally learned that running iin that situation is inefficient — or just felt that 21 yards was a bit out of range — we’ll never really know. Either way, he chose to call a pass play. This led to previously-referenced 17-yard completion to Kelce, which put the Chiefs in field goal position and set up the eventual victory.

Stop. Running. On. Second. And. Long. Please.

That’s it for Week 9 of Stacking the Box Score.


Leave a comment or reach out on Twitter (@ChiefsAnalytics) if you have questions or would like to see something new for next week. Thanks!