The Unexpected Fall of Khris Davis: Did Pitchers Figure Him Out?

Over the past three years, Athletics slugger Khris Davis has been a name that strikes fear into the hearts of pitchers. While his batting average hasn’t always been high, his slugging power is undeniable. Looking at home run totals from the 2016 to 2018 seasons, Khris Davis led all of Major League Baseball with 133 home runs (Figure 1), consistently maintaining a production rate of over 40 homers per year.

Figure 1

However, with 3/5 of the current season already in the books, Khris Davis has tallied only 16 home runs at the time of writing. Even accounting for time missed due to injury, Davis’s home run production rate is a far cry from his previous standards. Specifically, over the past three seasons, he averaged one home run every 12.75 at-bats; this year, that number has ballooned to 19 at-bats. At this pace, he may struggle to even reach the 30-HR mark. His adjusted OPS (OPS+) currently sits at just 98 (where 100 represents league average, and anything below is sub-par). What exactly happened to this former elite slugger?

From a results perspective, Khris Davis’s batted ball quality has taken a massive hit this year. We can measure this using two primary metrics:

1. Exit Velocity
2. Hard-hit rate

First, Khris Davis’s average exit velocity has dropped from an average of approximately 92 mph over the last three years to 89.8 mph this year.

Hard-hit rate measures the percentage of batted balls with an exit velocity of at least 95 mph. Over the past three years, Davis maintained a Hard-hit rate of nearly 50%, but this year it has plummeted to 40%, making him only slightly better than the league-average hitter. (For a full explanation of Hard-hit rate, see: http://m.mlb.com/glossary/statcast/hard-hit-rate)

There are many reasons why contact quality might decline. I have summarized the three most likely factors for Khris Davis:

1. Changes in pitcher strategy
2. Age (Davis is now over 30)
3. Injury (Typically durable, he spent time on the IL this May)

While the latter two are difficult to quantify with data—only the player truly knows his physical state—we can analyze whether MLB pitchers have changed their approach against him.

According to Figure 2, there hasn’t been a significant change in general pitch location this year (redder areas indicate a higher percentage of pitches in that zone; the left side represents the inside for a right-handed hitter, the right side represents the outside).

Figure 2

Digging deeper, we find that Davis’s performance against fastballs—his bread and butter—has seen a major downward revision. Figure 3 shows Davis’s annual wOBA and xwOBA against different pitch types. Both are advanced metrics used to evaluate hitting performance (xwOBA is the expected value of wOBA based on contact quality). Historically, Davis posted a wOBA/xwOBA near .400 against fastballs, but this year both metrics have regressed sharply to approximately .350. Additionally, Pitch Value (the batter’s performance against specific pitch types) shows that Davis’s performance against the fastball family is at a three-year low (Figure 4), dropping from the low 20s to just 6. This led me to wonder: has the way pitchers deploy fastballs against him changed?

Figure 3

Figure 4

Figure 5 shows the pitch location distribution of “fastball-type” pitches (4-seamers, cutters, splitters) against Khris Davis this year. Again, the left side is the inside for a righty. We can see that compared to previous years, pitchers have begun pounding the high-and-inside corner and locations elevated above the strike zone. The reason behind this is telling!

Figure 5

I then looked at Khris Davis’s wOBA across the 3x3 strike zone grid over the last four years (Figure 6). As a reminder, wOBA is more effective than traditional stats at assessing overall hitting value. We can see that this year, Davis’s wOBA is significantly lower across the entire inner half of the plate (the area circled in light yellow). In the past, while his wOBA was also low in the high-and-inside corner, the surrounding zones were “hot zones.” If a pitcher missed their target slightly, the ball would land in Davis’s wheelhouse and he would make them pay. However, this year, that high-and-inside weakness lacks the protection of neighboring hot zones, making it an easy target for pitchers to exploit.

Figure 6

In summary, I believe the primary cause of Khris Davis’s decline this year is likely physical factors (he spent 10 days on the IL with a left hip injury), which have led to a decline in batted ball quality and poor coverage of inside pitches. Pitchers have identified this vulnerability and are leaning into it—jamming him with high-and-inside fastballs. Since Davis is currently unable to handle these pitches, it has resulted in his sluggish performance.

If our Athletics slugger can adjust in the second half and regain his powerhouse form, the A’s will see a massive boost in their competitiveness for an AL Wild Card spot!

Embed from Getty Images

Khris Davis Photo Credit: Hannah Foslien/GettyImages

Data Sources: FanGraphs, Baseball Savant, Baseball Reference