Zac Gallen & Stephen Vogt: The League of Shadows Battery

The art and science of pitching is a complex endeavor in pursuit of a simple goal: see that guy, or gal, in the batter’s box? Get him, or her, out. There are myriad ways to try to achieve that goal, and analyses of spin axes, pitch sequencing, and defensive positioning, just to name a few, all come into play. But if you had to distill a good way of “getting somebody out” to two simple directives, you could do a lot worse than:

a) Stay away from the middle of the plate

b) Get the batter to swing and miss at your pitches

If you combine those two in a certain way, Zac Gallen was the third best starting pitcher in baseball in 2020. Let me explain. Looking at the Statcast data for all pitchers, who threw at least 60 innings in 2020, for the swing-and-miss part I simply took their “Whiff %”. I then decided to use a proxy for staying away from the middle of the plate by just taking the pitcher’s “Edge%”. As best as I can tell, the Edge % is the same thing as the percentage of pitches thrown in the Shadow of the strikezone, which is “roughly one ball width inside and one ball width outside of the zone (Statcast)”. I then simply added the two values together, to come up with a made up “Edge&Whiff” number. Here is the top 10 from the year 2020.

Name2020 IPEdge%Whiff%Whiff+Edge%
Jacob deGrom68.045.841.086.8
Shane Bieber77.141.940.782.6
Zac Gallen72.048.530.478.9
Gerrit Cole73.043.134.277.3
Aaron Nola71.146.031.377.3
Lucas Giolito72.140.536.677.1
Kenta Maeda66.241.434.876.2
Carlos Carrasco68.043.332.776.0
Max Scherzer67.142.832.675.4
Dylan Bundy65.245.629.575.1
Courtesy MLB Statcast

That’s a pretty good group to belong to, if you’re an MLB starter. We have Cy Young winners, All-Stars, you name it. In terms of Zac Gallen, note that his membership in this made up club is predicated upon his Edge%: his Whiff% tops only that of Dylan Bundy, while his Edge % is the highest on the list. As it turns out, out of all pitchers, who threw at least 60 innings in 2020, Gallen’s Edge % of 48.6 was the best in MLB.

With that being said, I wanted to see which edges of the strikezone Gallen attacked the most frequently in 2020. First, let’s take a look at his four-seam and cutter locations. The four-seamer is on the left, and the cutter is the right image.

With both of his fastballs, Gallen was heavily targeting them to his glove side. There is a “hot spot” for the cutter down and to the glove side on the chase, but notice how the fastballs are mostly clustered around the outer edge of the strikezone – giving visual confirmation to Gallen’s high Edge % from above – and how relatively few of them were aimed towards the upper edge of the strikezone and to Gallen’s arm side.

What about the curveball and the changeup? Below, the curveball is the image on the left, while the change is the image on the right.

Gallen’s command of the changeup was fantastic in 2020, resulting in a ridiculous 44.1% whiff rate. But my other main takeaway is that the curveball and changeup are thrown right around the bottom edge of the zone: for the most part, Gallen is not trying to fool you left or right with his changeup and curveball.

What do we have so far? In 2020, Zac Gallen was living in the Shadows. Specifically, on his fastballs, he preferred the edge away from the righties and inside to lefties, while on his changeup and curveball, he tried to get hitters to swing at pitches at, or down below the knees. I will get to Stephen Vogt, I promise.

With close to 50% of Gallen’s pitches thrown in the Shadow of the strikezone, how often did batters swing at those pitches, compared to league average?

Courtesy MLB Statcast

The swing rate against Gallen in the Shadow part of the zone was right in line with the league average: batters swung at 51% of the pitches Gallen threw in the Shadow, as compared to 52% for the league average. One observation that I think speaks to the deception of Gallen’s stuff is that hitters only swung at 65% of his pitches in the Heart of the zone, as opposed to 73% for the league average.

So Gallen threw the majority of his pitches around the edges of the zone, and batters swung at about a half of them, in line with the league average. It sure would be great if the takes were called strikes, wouldn’t it? We’re ready for the second member of the League of Shadows to take the stage.

Fangraphs projects Stephen Vogt to appear in about 65 games in 2021, with the bulk of the catching duties going to Carson Kelly. Fangraphs also projects Vogt to be the worse overall fielder of the two. However, there was one thing Vogt did exceptionally well in 2020, and that was framing pitches.

I will leave it up to the Diamondbacks front office and coaches to decide, whether Vogt’s marked improvement in framing is real or not. However, based on Statcast, in 2020 Vogt was the fifth best pitch framer in baseball, in terms of converting non-swings in the Shadow of the zone into called strikes.

Courtesy MLB Statcast

Were there any particular areas, where Vogt was most effective? Vogt was most successful in Zone 16 – away to righties and inside to lefties, where he converted 69% of non-swings in the Shadow zone into called strikes, 11th best baseball. His second best outcome was in Zone 18 – down below the knees, where he converted 60.9% of non-swings into called strikes, 7th best in baseball. Here is how Vogt compared to Carson Kelly in those two zones (I couldn’t find Varsho’s framing data on Statcast).

NameZone 16 (wide)Zone 18 (down)
Stephen Vogt69.0%60.9%
Carson Kelly64.2%52.9%
Courtesy MLB Statcast

What does it all mean? There is obviously way more that goes into catcher-pitcher pairing than just this. At the same time, we have a young pitcher, who has thrown about half of his pitches around the edges of the zone in 2020. Two particular edges, to be exact. He also generates swings on those pitches at about the league average rate. If Gallen wants to keep working mostly in those areas of the zone going forward, the Diamondbacks have a catcher on their staff, whose strength is framing pitches in those exact areas. If batters swing at those pitches, great – that’s how you get an average exit velocity of 87mph. If they take those pitches, Gallen has help back there to convert those pitches into called strikes. Zac Gallen and Stephen Vogt: The League of Shadows battery. Potentially coming soon to a ballpark near you.

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