5 pitchers who made clear improvements with NY Mets under Jeremy Hefner

Welcome to Jeremy Hefner's Pitching Lab. NY Mets pitching coach Jeremy Hefner has a well-earned reputation for helping his pitchers get the most from their abilities. Sometimes, it can be through mechanical adjustments in motion, delivery, or release point. Other times it might be because of his personized coaching philosophy of advanced analytics, adding or eliminating certain pitches in a player's arsenal.

Jeremy Hefner is a proponent of his pitchers adding the "kick" change to their arsenal. It features a changeup style grip and generates spin like a changeup, but has a splitter-like movement and is thrown harder. It fades less than a traditional changeup and moves horizontally to the pitcher's arm side. It's essentially a changeup with a distinct "kick" from the middle finger that alters the ball's spin and movement.

Hefner has helped his pitchers refine their game and they have made clear improvements. Pitchers who may only have had modest success with other teams have found that Hefner’s guidance has helped them attain a success that they had not previously experienced. Here are some notable examples:

Mets Who've Been Saved by Jeremy Hefner: Honorable Mentions

Tylor Megill – Introducing the "Kick Change"
Tylor Megill has been with the Mets for five seasons with a career mark of 25-25. He has also added the kick change, a hybrid pitch blending elements of a changeup and a splitter, to his arsenal under Hefner's guidance. This addition has contributed to his improved and more consistent performance early in the 2025 season.

David Peterson – Post-Injury Resurgence
David Peterson has been with the Mets for six years. After four seasons, his record was only 18-21. Returning from hip surgery, David Peterson worked with Hefner to refine his mechanics and pitch sequencing. This collaboration resulted in a record of 10-3 with a career-best 2.90 ERA over 21 starts in 2024, along with a standout postseason performance, including his first postseason save and win.

Jose Quintana - Signed with the Brewers
In the 2024 MLB season, José Quintana experienced a notable resurgence with the New York Mets, posting a 10–10 record. Jeremy Hefner played a pivotal role in his improvement by adjusting his pitching approach and encouraging him to induce more swings on pitches outside the strike zone. This performance contributed to the Mets' deep playoff run and showcased Hefner's effective coaching strategies. Quintana signed a one-year contract with the Brewers.

Luis Severino - Signed with the Athletics
Severino experienced a significant resurgence with the New York Mets in 2024, rebounding from a challenging 2023 campaign. Under the guidance of Jeremy Hefner, Severino made strategic adjustments that contributed to his improved performance, posting a record of 11-7. Severino signed a one-year contract with the Athletics.

5. Paul Blackburn – Refining pitch movement

Paul Blackburn arrived in New York at age 30 after an eight-year career with the Athletics. He brought along with him a career mark of 21-26. Jeremy Hefner has been a significant influence on the progress that Paul Blackburn has shown since joining the Mets, helping him refine his pitching repertoire and situational pitch selection.

Hefner worked with Blackburn to add more movement to his pitches, especially his sinker and sweeper. This included modifying his grip which has added more run to the sinker and horizontal movement to the sweeper.  Hefner also has Blackburn experimenting with a cutter instead of a four-seam fastball, while emphasizing better use of his changeup. This strategy promotes keeping the ball on the ground and limiting hard-hit balls. 

Hefner and the Mets staff have cleaned up some of Blackburn's motion issues, allowing him to maintain better velocity and location deeper into games. The Mets' guru is known for helping pitchers improve by enhancing game planning. By working with the Mets’ catchers and analytics team, Blackburn has become better prepared for specific hitters.

Hefner has helped Blackburn understand the art and science of pitching, allowing him to make more informed decisions on what pitches to throw and when. He has provided a open environment where Blackburn can feel free to adapt and improve, rather than being constrained by set ideas about his abilities. 

4. Reed Garrett – Pitch Selection and Diversification

Reed Garrett came to the NY Mets at age 30 after stops with the Tigers, Orioles, Nationals and two years in Japan. His total major league career record stood at a mere 0-1. Jeremy Hefner has been instrumental in helping Garrett diversify his pitch selection and refine his pitching mix by reducing reliance on his four-seam fastball, while at the same time incorporating a cutter, sinker, sweeper, and splitter.

This strategic shift has significantly impacted Garrett's effectiveness and led to a breakout 2024 season that saw Garrett post a 3.77 ERA over 53 games. His success continued into 2025, with a remarkable 0.70 ERA over his first 26 appearances, including eight consecutive scoreless outings. Hefner has instilled confidence in Garrett by encouraging him to trust the process and believe in his abilities, even when facing challenges.

Hefner's coaching extends beyond technical skills. His focus is also on the mental aspects of the game. This has helped Reed Garrett maintain a positive attitude and resolve. The two men have developed a high level of trust due to the supportive and genuine nature of their relationship. Reed Garrett's emergence as a dominant reliever and setup man is largely attributed to the coaching and support that he has received from Jeremy Hefner. 

3. Clay Holmes – Adopting a New Style Changeup

Clay Holmes came to the NY Mets at age 32 after four years with the Pirates and four more with the Yankees, where he was used almost exclusively out of the bullpen. Jeremy Hefner has helped Clay Holmes by guiding him through his transition from a reliever to a starting pitcher. He has provided a clear plan and process for his games while emphasizing the importance of a strong relationship between players and coaches. Hefner's influence has been crucial in Holmes' successful adaptation to his new role.

Hefner had Holmes add a "kick" change to his pitching arsenal. It features a changeup style grip and generates spin like a changeup, but has a splitter-like movement and is thrown harder. It fades less than a traditional changeup and moves horizontally to the pitcher's arm side. It's essentially a changeup with a distinct "kick" from the middle finger that alters the ball's spin and movement. This adaptation has contributed to the Mets' rotation achieving a collective 2.89 ERA through 38 games in the 2025 season.

Jeremy Hefner has helped Clay Holmes understand the changes required to be a starting pitcher, both physically and mentally. He emphasized the importance of having a specific plan for each game, including strategies for attacking each hitter. He has emphasized the importance of building strength and conditioning routines to support Holmes' transition to a starting pitcher. 

Hefner has shown a personal interest in Holmes' development, making sure to utilize analytics in a way that is meaningful to the player. Jeremy Hefner's guidance and approach have helped Clay Holmes to build confidence in his ability to succeed. 

2. Griffin Canning – Embracing Analytics

Griffin Canning arrived in New York at age 29 after a five-year stint with the Angels, bringing with him a career record of 25-34. Jeremy Hefner helped Canning focus on his strengths, particularly his slider, and developing a more confident and strategic approach on the mound. Hefner has emphasized the importance of relying on his best pitches and using a more proactive approach against all hitters.  Canning had struggled through a challenging 2024 season with the Los Angeles Angels, where he posted a 5.19 ERA. He signed a one-year, $4.25 million deal with the Mets. This move was influenced by the team's advanced use of pitch technology.

Hefner has made significant adjustments to Canning‘s pitching arsenal, including the addition of the afore mentioned kick change, a changeup-splitter hybrid pitch that has gained popularity among Mets pitchers. This pitch has been instrumental in Canning's improved performance, contributing to his 5-1 record in the early part of the season.

Jeremy Hefner has significantly improved Griffin Canning's performance on the mound. He has emphasized the importance of relying on his best pitches and using his strengths. Canning has begun leaning more heavily on his slider and developing a more confident and strategic approach on the mound. This more proactive approach against hitters has made an important contribution to Canning’s success. 

Griffin Canning's resurgence with the New York Mets in the 2025 MLB season is a testament to the collaborative efforts between he and his pitching coach. Canning's success in refining his delivery and incorporating new pitches emphasizes the importance of a knowledgeable staff in translating data into actionable feedback. It is a testament to the positive impact of Jeremy Hefner's coaching and the Mets' pitching program. 

 1.  Sean Manaea – Arm Slot Adjustment

Sean Manaea came to the NY Mets at age 32 after an eight-year career with the Athletics, Padres, and Giants. His lifetime MLB totals stood at a modest 65-56. Sean Manaea's resurgence with the New York Mets in 2024 can be significantly attributed to the guidance of pitching coach Jeremy Hefner. He encouraged Manaea to experiment with a lower arm slot, inspired by Chris Sale's success with a similar approach. He also helped Manaea refine his changeup and other pitches, ultimately transforming him into a more complete pitcher. These adjustments led to a 2.63 ERA since late July 2024, with Manaea leading left-handed pitchers in innings pitched during that span.

Hefner created an environment where Manaea felt comfortable experimenting with his throwing motion and bouncing ideas off him. This allowed Manaea to find a new feel on the mound and make adjustments that significantly impacted his performance. He had Manaea focus on his core pitches, reducing the strain on his arm and making him more of a strategic pitcher rather than relying solely on velocity. 

Hefner was instrumental in helping Manaea utilize analytics to improve his pitching. He is known for tailoring his approach to each pitcher, understanding their strengths and weaknesses and helping them develop their individual skills. His experience as a former major league pitcher had allowed him to build trust with Manaea, making it easier for Manaea to accept and implement changes. 

Recognizing the benefits of the Mets' coaching and development system, Manaea re-signed with the team on a three-year, $75 million contract in December 2024. He is recovering from a right oblique strain sustained during spring training and is expected to begin a rehab assignment soon. In summary, Jeremy Hefner's coaching has been instrumental in revitalizing Sean Manaea's career, with strategic adjustments leading to improved performance and a renewed commitment to the Mets organization.