I believe that pitches aren’t thrown in a vacuum, and the effectiveness of one pitch is certainly affected by the pitches that preceded it. Thus, I wanted to identify the most- and least-potent 1-2 pitch combinations in the 2018 Major League Baseball season. To accomplish this, I built a Pitch Combo Effectiveness Tool based on all 2018 pitches thrown in the major leagues.
The approach I took was to evaluate every pitch as the second pitch in a 1-2 combo (forcing us to exclude first pitches in an at-bat). I defined these pitch combos using the pitcher, the pitch types of both the first and second pitches (e.g. “four-seam fastball followed by a curveball”), and the pitch location change from the first to the second pitch (e.g. “the second pitch was further down and more inside than the first pitch”). I then gauged the effectiveness or value of these pitch combinations using the sum of the wOBA added for both the first and second pitches. Lastly, to ensure we were only looking at common pitch combos, we filtered the results to pitch combos observed at least 10 times in 2018.
The chart showing every pitch combo is below, and you can click it to go to the full tool and results:
So how can we use this Pitch Combo Effectiveness Tool and what can we learn? The chart above is nice to look at, but it’s not that helpful by itself. However, the depth of detail is great and the patterns are surprisingly strong and insightful once you start focusing. For each pitch combo, we also report average pitch speed change and difference in breaking action between the first and second pitches. We also measure the usage rate of that combo for the pitcher.
The results show clear patterns and trends in what is most and least effective for individual pitchers. As an example, we’ve captured the Max Scherzer results below. Scherzer throws a lot of “four-seam fastball, four-seam fastball” combinations, but they are far more effective when the second pitch is more inside to the hitter and/or further up in the zone. Almost all of his negative-wOBA-added pitches (good for the pitcher) follow this location movement trend. Pitches that defy that trend are almost all further outside and/or lower in the zone.
There are several more examples like this, and the trends are unique to the individual pitcher. This shows us different pitchers have different 1-2 combos that serve them best, and understanding this can lead to superior pitch sequencing.
I write about baseball because it's fun. My writing is very data-driven, which is often not fun. I aspire to someday write the 'Infinite Jest' of baseball advanced analytics. I'm also a technology transformation consultant and owner of a very shed-y dog.