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Biomechanics behind Walker’s 2020 rejuvenation

Taijuan Walker was only at the Driveline Baseball facility in Kent, Wash., for a few days after the 2019 season.

But the right-handed pitcher left with the data, tools and plan he needed to set in motion a bounce-back 2020 season that ultimately led him to the Mets.

The diagnosis? After tests and evaluations for the 2018 Tommy John surgery patient, Walker made some minor tweaks to his mechanics and got a few spin numbers he could target with his offspeed pitches. The results? A 2.70 ERA in 11 starts last season, which put him in position to sign a two-year, $20 million deal with the Mets in February.

“It’s pretty special to see someone come in for a handful of days, absorb the information, ask a ton of really good questions and then take that stuff and run with it and put in an unreal amount of work in the offseason on his own,” Bill Hezel, Driveline’s director of pitching, said in a recent phone interview. “And more importantly, see that translate onto the field for him in such a big way. I’m excited to see what he does this year.”

As are the Mets, who are counting on Walker to be a key piece of their rotation as they try to tap into the upside he showed in the shortened 2020 season.

In order to get those results, Walker dove head-first into the technology and numbers provided by Driveline, the analytics-based player development organization with its own biomechanics lab.

Walker started by getting a full comprehensive assessment: a physical evaluation; force-plate testing; a breakdown of his arsenal; and getting markered up for motion capture as he threw a short bullpen session. From there, the Driveline staff talked to Walker about how his numbers stacked up against other pitchers who had come through its lab, good and bad, and offered recommendations.

While there was a focus on his “trunk orientation” (making sure his torso didn’t rotate too early during his delivery), the more tangible change came in regard to his pitches. The staff focused on having Walker shift the spin direction on his splitchangeup and cutter, which has since turned into more of a slider. They wanted the splitchangeup to get more vertical separation from his fastball, and the slider to get more horizontal movement without sacrificing too much velocity.

“We felt like a goal of five inches of glove-side movement and the pitch still needed to average over 85,” Hezel said.

Walker delivered — recording 4.9 inches of horizontal movement on his slider, per Baseball Savant, while averaging 85.2 mph on the pitch. The Driveline staff also told Walker that if he could hit those numbers with his slider, he should use it more often, because it was a strong pitch. He followed through, throwing it 21.5 percent of the time compared to 15 percent in 2017 — when it was still a cutter during his last full season — with the whiff rate increasing nearly five percentage points to 24.4.

Especially given the shortened nature of the season, though, Walker’s 2020 numbers raise the question: Are they sustainable? Hezel said that although pitches like sliders can be volatile because of their gyroscopic spin, Walker now has a benchmark for where the pitch’s spin data should be, with some help from Rapsodo, and even how it should look coming out of his hand, thanks to the Edgertronics high-speed footage.