Luke Weaver’s Pitching Evolution with the New York Yankees

When Luke Weaver arrived in Arizona in 2019, he introduced a new approach to improving his pitching arsenal by utilizing a Rapsodo pitch-tracking machine. This innovation allowed him to analyze his pitch mechanics, although initially, he was uncertain about the metrics he should focus on. After consulting with the company, Weaver began to refine his pitches, particularly his curveball and cutter, leaving his fastball and changeup as his reliable mainstays.

In 2019, Weaver enjoyed a successful season with a 2.94 ERA in 12 starts, aided by an increased reliance on curves and cutters. However, the following seasons proved challenging as he struggled to maintain consistency, recording an ERA over 6.00 in three of the next four seasons while playing for five different teams. During this period, he experimented with various pitches, including sliders in 2021 and a knuckle curve in 2023.

Weaver’s pronation, meaning his earlier release with his index finger during pitches, presented challenges in mastering the curveball. Despite earlier efforts with the St. Louis Cardinals‘ Adam Wainwright in 2017, this mechanical tendency often led to early releases and less effective spins on the ball.

Currently with the New York Yankees, Weaver has adjusted his approach, throwing the curveball less frequently and seeing improvements in his fastball and cutter performance. This adjustment has been crucial in his development into a closer for the team, which is progressing towards the World Series.

“It’s been a journey,” Weaver acknowledged late into the season. “But everything feels good now.” His evolution with the Yankees began almost immediately by improving the spin efficiency of his four-seam fastball, which had lost its “ride”. With a slight adjustment in grip, Weaver increased his spin efficiency from 92 percent to 94 percent, enhancing the fastball’s movement.

Furthermore, Weaver’s transition to the bullpen enabled him to throw with increased velocity, complimenting his low release point due to drop-and-drive mechanics, ultimately leading to one of the most effective four-seamers in the league. His improvement is reflected in the Stuff+ statistic, showcasing significant year-over-year advancements.

The Yankees also suggested subtle refinements to his cutter and developed a new grip for his changeup, switching from a two-seam to a one-seamer, resulting in unprecedented drop and swing potential. The collaborative effort between Weaver and the Yankees’ coaching staff, particularly pitching coach Matt Blake, has significantly contributed to his resurgence.

“The Yankees have been great,” Weaver said, expressing gratitude for the support and guidance provided by the team’s coaching personnel.

Photo of Luke Weaver by Vincent Carchietta, Imagn Images.