Former FSU Ace Luke Weaver’s Remarkable Turnaround: How 2024 Became His Breakout Season
Image from pinstripealley.com
Luke Weaver graduated from FSU in 2014 and made his major league debut for the Cardinals in 2016. Over the next 8 seasons, he would play for 6 different MLB teams and work his way around the league as an average starter. Weaver amassed a career 5.15 ERA before 2024, and a woeful 6.5 ERA in 2022 and ‘23. In 2024, however, he put together a season (especially back stretch) that no one could have seen coming. No one except the Yankees bullpen coach, Matt Blake, that is.
The changes made by the Yankees pitching staff resulted in a dramatic positive increase for Weaver in many advanced stats. According to Baseball Savant, he was in the 92nd percentile in Pitching Run Value in 2024: a 90-percentile increase from 2023. His fastball and changeup Run-Value both increased by 77 percent, and his career ERA+ of 89.25 jumped dramatically to 142. The BAA (batting average against) of Weaver’s 3 most-used pitches dropped by an average of 105 percentage points each. (.311 to .177 on his fastball, .316 to .172 on his changeup, and .218 to .182 on his cutter)
What changes could Weaver and the Yankees have made to change the course of his career? Let’s break it down into 2 parts: the changes made to his pitches and grips, and his approach and mechanics.
Pitch Grips and Statistics
From 2016 to 2022, Weaver threw his fastball 57% of the time, but it was truly an average pitch. In 2024, all metrics used to measure the success of his fastball improved significantly.
The velocity was up almost 2 miles per hour (94.0 in 2023 to 95.7 in ‘24), the vertical break increased from 16 to 18.6 and he saw a decrease in horizontal break by about an inch. The spin rate also improved by almost 100 RPMs. FanGraphs stuff+ rated his 2023 fastball an 88, meaning 85 percent of all fastballs in the majors were expected to perform better. His 2024 fastball was rated a 142: or in the 98th percentile of all fastballs in the Major Leagues.
The picture below shows the changes in his grip from ‘23 to ‘24. You can see how his hand is shifted more towards the center of the ball, as well as his thumb placed more under rather than to the side, which helped result in these improved metrics.
Weaver’s fastball grip in 2023 vs 2024
A combination of fastball and changeup is one of the most effective a pitcher can have. The closer the changeup can look to the fastball the more potent it will be: this means a closer difference in velocity but a significant difference in movement. Luke Weaver found the magic touch and improved in both of those measures in 2024.
His 2023 changeup was 8 miles per hour slower than his fastball and had a drop differential of 8’, while his 2024 changeup was 7 mph slower and had a drop differential of 14’. Throwing harder and creating that difference in break made his changeup dramatically more effective. FanGraphs rated his 2023 changeup an 83 compared to a 107 in 2024. The swinging strike rate against the pitch almost doubled, and the whiff percentage increased from 32.3% to 48%. The spin rate of the pitch also increased by over 150 RPMs.
The improved spin and results can be attributed to Weaver and the Yankee’s profound understanding of the importance of seam-shifted wake. The concept of a seam-shifted wake was first explored by researchers and pitchers to explain why certain pitchers' pitches seemed to "move" more than others, even with similar velocity and spin rates. The seams of the ball create small disturbances in the air around it, and how the pitcher positions the ball in their hand can affect how the air flows around these seams during the pitch.
By understanding seam-shifted wake, pitchers, like Weaver, can improve their pitches' effectiveness by maximizing the movement of the ball. Combined with his improved fastball, his changeup became lethal.
Approach and Mechanics
Obviously, one of the most important parts of being an effective pitcher is knowing what pitches to throw. Weaver’s change in pitch selection and usage percentage was another crucial adjustment he made to become one of the best relievers in baseball.
In 2023, his usage percentage of pitches looked like this:
Graph via Baseball Savant
After moving to the bullpen in 2024, these were his stats:
When throwing to right-handed batters, he scrapped the use of his curve and slider/sweeper completely, and nearly doubled the use of his changeup and cutter. To left-handed batters, the 16% usage of his curve in 2023 dropped all the way down to 1%, and he used the changeup on 36% of his pitches to lefties in 2024, compared to 25% in 2023.
Another change can be seen in his mechanics. He simplified his lower half mechanics to be closer to a slide step on every pitch. He significantly lowered his leg kick, and despite this, gained almost 2 miles per hour on his average fastball. The gif below shows the difference in his mechanics from 2023 to 2024. Comparing his windups, his 2024 motion appears to be a much more efficient transfer of energy, as he gets down the mound further and quicker.
Weaver’s windup in 2023 (left) compared to 2024 (right).
This change could also have helped with consistency, as Weaver threw pitches on the black at a significantly higher clip than most MLB pitchers. Throwing pitches on the corners is crucial for keeping batters guessing and staying ahead in the count, and Weaver did just that. His strike percentage was lower than the league average (43.7% compared to the league average 49.9%) as well as his pitches thrown out of the zone (56.3% to 51.1%). However, he threw 44% of his pitches at the edges of the zone, which is 5 percent above league average. The image below shows all of his pitches thrown in 2024, with the highlighted ones representing those at the edge of the zone.
graph via Baseball Savant
Conclusion
Overall, Luke Weaver’s transformation in 2024 serves as a testament to the importance of both pitch development and strategic adjustments. By tweaking his pitch grips and focusing on maximizing the effectiveness of his one-two punch of fastball and changeup, Weaver made substantial improvements in almost all pitching metrics.
The changes made by Weaver and the Yankees coaching staff in 2024 demonstrate the significant impact that targeted adjustments can have on a player’s career, turning a once-average starter into one of the most effective relievers in the league.
It will be interesting to see if Luke Weaver can continue his dominance in 2025, or if batters will adjust to this new look. With only one more year on his Yankees contract, another year of success could put him in position for a huge pay increase in 2026.