Walker Buehler figured out his slider and cutter

Yesterday when I was perusing links that came across my Twitter feed, I stumbled upon a fantastic piece written by Shi Davidi and Ben Nicholson-Smith regarding the recent technology advancements that the game of baseball has seen. For much of the piece, the perspective comes through Driveline Baseball’s President and Founder Kyle Boddy. After explaining the ways that player development has changed and how this data movement is a positive thing for baseball, the piece turns into a story that involves Boddy and young Dodgers right-handed pitcher Walker Buehler.

Buehler messaged Boddy asking him why he wasn’t getting more strikeouts. He asked for advice. Boddy got back to him with this...

A problem for some, an opportunity for others. A few days after their first chat, Boddy called again. He had analyzed Buehler’s pitch data — how it moved and how hitters would see it — and determined that he needed a hard pitch with lateral break, like a cutter. “That’s the biggest hole in your game,” Boddy told him.

The story later goes on to mention that after messing around with a few grips, Buehler found a new pitch, which looked to be an improved form of his slider. He started using it in an what looks to be August 22nd start against the Cardinals, further evidenced in an October interview he had with Eno Sarris.

“Oh yeah, that’s my slider and my cutter. Velocity, right?” Buehler laughed at the mini-graph I thrust in his face. “I changed my grip on the slider in St. Louis and that took some firmness off of it.”

From that one start in St. Louis, he was on another level. All throughout September, into the World Series, Buehler was one of the more dominant pitchers in the game. His improvements can be evidenced by the numbers.

• From April 23rd to August 18th: 375 results, .264 wOBA, .264 xwOBA, 26.5% K%, 11.2% SwStr%, 9.4 LA
• From August 19th to November 1st: 279 results, .218 wOBA, .248 xwOBA 31.2% K%, 13.9% SwStr%, 7.8 degree LA

This coincides right with the brand new development of Buehler’s slider. Boddy mentioned that Buehler needed a “hard pitch with lateral break.” He ended up making similar improvements with thispitch, as according to Brooks Baseball, his slider did gain horizontal movement, jumping from 5.16 to 6.48 inches in those two respective timeframes. All despite taking some velocity off of it (87.6 MPH to 85.3 MPH).

The results match up with this change too. While still very good, Buehler’s slider before August 22nd ranked 53rd out of 294 pitchers with at least 100 results in xwOBA. After that point (including the playoffs), it ranked 32nd out of 233 (minimum 50 results). As for swinging-strike rate, he ranked in the bottom-third of baseball with his slider before that late August start. After, he jumped to the top half.

Now I want to jump to the more interesting part of Buehler’s adjustments. Mentioned above from both the Sarris and Dividi/Nicholson-Smith interviews was a cutter. A noticeable trend throughout the season for him was his increased usage in his cutter. After it being almost a non-factor in the month of May, he spiked his usage of it from ~5-8 percent in the middle of the season. In the final months of the regular season it had gone above 10 percent. In the postseason, he used it roughly 20 percent of the time.

Using the same date constraints I used for the slider above, we’ll look at what changed with his cutter. He saw a significant velocity bump along with some added vertical movement.

The pitch had a shaky start in throughout the month of September (.382 wOBA), but it became a useful tool in the postseason (.160 wOBA). He turned it into one of the more movement-heavy cutters in the game.

Pure filth.

If Buehler can pair his devastating slider with a 95+ MPH four-seamer and sinker, while improving his raw cutter, we could witness any even further breakout in 2018. There was already a reason he was considered one of the better young hurlers in the game, but now the league should be but up on an even greater notice.

Walker Buehler has maybe not even came close to his fullest form yet.

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Patrick Brennan loves to research pitchers and minor leaguers with data. You can find additional work of his at Royals Review and Royals Farm Report. You can also find him on Twitter @paintingcorner.