Mark Edward Leiter Jr. Bio
Mark Edward Leiter Jr. is an American professional baseball pitcher for the Athletics of Major League Baseball. He has played in MLB for the Philadelphia Phillies, Toronto Blue Jays, Chicago Cubs, and New York Yankees. Leiter was born on March 13, 1991, and attended Toms River High School North in Toms River, New Jersey. He played college baseball at the New Jersey Institute of Technology before the Phillies selected him in the 22nd round of the 2013 MLB draft. He made his MLB debut with Philadelphia in 2017. He currently resides in Lanoka Harbor, New Jersey.
Early Life and Background
Leiter grew up in New Jersey and attended Toms River High School North. His baseball upbringing was deeply influenced by his family legacy. His father, Mark Leiter, and uncle, Al Leiter, both enjoyed lengthy careers as pitchers in Major League Baseball. Al Leiter achieved particular prominence, winning a World Series with the Florida Marlins in 1997 and earning two All-Star selections. This family connection provided Leiter with both inspiration and valuable guidance as he developed his own pitching skills during his teenage years.
After completing high school, Leiter continued his academic and athletic career at the New Jersey Institute of Technology, where he played college baseball. His performance at the collegiate level caught the attention of professional scouts, leading to his selection in the 2013 MLB draft.
Path to Professional Baseball
Leiter entered the professional ranks immediately after being drafted by the Philadelphia Phillies in the 22nd round of the 2013 MLB draft. He signed with the organization and began his professional career that same year. His initial season showed considerable promise as he compiled a 4-0 record with a remarkable 1.20 earned run average across three minor league levels, logging 45 innings of work between the GCL Phillies, Clearwater Threshers, and Lakewood BlueClaws.
Over the next several seasons, Leiter steadily climbed through the Phillies minor league system. He continued developing his craft as both a starter and reliever, accumulating experience at every minor league level. His versatility and consistent performance laid the foundation for his eventual promotion to the major leagues in 2017.
Mark Edward Leiter Jr. Career
Philadelphia Phillies (2017-2018)
Leiter received his first major league call-up on April 18, 2017, and made his MLB debut on April 28 of that year. His rookie season proved to be a significant learning experience as he appeared in 27 games, making 11 starts. He finished the season with a 3-6 record, a 4.96 earned run average, and 84 strikeouts across 74 innings pitched. The exposure to major league competition accelerated his development and gave him valuable experience navigating lineup adjustments at the highest level.
Leiter began the 2018 season on the disabled list. After being activated, he was optioned to Triple-A Lehigh Valley before the Phillies designated him for assignment. His time in Philadelphia ended when the Toronto Blue Jays claimed him off waivers on September 1, 2018. He made eight appearances for the Blue Jays that September, struggling to a 13.50 earned run average with nine strikeouts across 6⅔ innings before the Blue Jays designated him for assignment later that November.
Recovery and Minor League Journey (2019-2021)
On March 17, 2019, the Blue Jays announced that Leiter would miss the entire season after undergoing Tommy John surgery. The injury forced him to rebuild his arm and career trajectory during a critical period. He elected free agency following the 2019 season and signed a minor league contract with the Arizona Diamondbacks in February 2020. The COVID-19 pandemic canceled the minor league season that year, leaving Leiter without a regular competitive outlet. He briefly joined the Somerset Patriots of the Atlantic League before that season was also canceled.
Leiter signed with the Detroit Tigers organization in March 2021 and split the season between Double-A Erie SeaWolves and Triple-A Toledo Mud Hens. He made 25 appearances, posting a impressive 10-8 record with a 3.77 earned run average and 145 strikeouts. The strong performance restored his confidence and demonstrated his ability to compete at the Triple-A level, setting the stage for his return to Major League Baseball.
Chicago Cubs (2022-2024)
Leiter signed a minor league contract with the Chicago Cubs in December 2021. His contract was selected to the major league roster on April 16, 2022, marking his return to MLB after three seasons. On August 16, 2022, Leiter recorded his first career save in a game against the Washington Nationals. He finished the season with a 2-7 record and 3.99 earned run average, making 35 appearances and registering 73 strikeouts across 67⅔ innings.
The 2023 season represented Leiter’s most productive major league campaign. After being designated for assignment in January and clearing waivers, he re-signed with the Cubs on a minor league contract before earning a roster spot in spring training. He made 69 relief appearances, posting a 3.50 earned run average with 77 strikeouts and four saves across 64⅓ innings. His ability to handle high-leverage situations made him an integral member of the Cubs bullpen.
In 2024, Leiter appeared in 39 games for the Cubs before the trade deadline. He compiled a 2-4 record with a 4.21 earned run average and 53 strikeouts over 36⅓ innings. On July 30, 2024, Chicago traded him to the New York Yankees in exchange for infielder Ben Cowles and pitcher Jack Neely.
New York Yankees (2024-2025)
Leiter joined the Yankees bullpen for the final stretch of the 2024 season. He made 21 appearances down the stretch, posting a 2-1 record with a 4.98 earned run average and 33 strikeouts across 21⅔ innings. The opportunity to pitch meaningful games in late-season pressure situations proved valuable for his development.
The Yankees retained Leiter for the full 2025 season, where he served as a reliable bullpen option. He made 59 appearances, compiling a 6-7 record with a 4.84 earned run average, 54 strikeouts, and two saves across 48⅓ innings. On November 21, 2025, the Yankees non-tendered Leiter, making him a free agent.
Oakland Athletics (2026-Present)
On December 17, 2025, Leiter signed a one-year contract worth $2.85 million with the Oakland Athletics. The deal marked a new chapter in his career as he joined a rebuilding organization seeking to develop young talent around experienced contributors. Leiter’s versatility and proven ability to pitch in various roles made him an attractive addition to the Athletics bullpen.
Pitching Style and Strengths
Leiter has demonstrated throughout his career the ability to transition effectively between starting and relief roles. His fastball command and ability to generate swings and misses with his secondary offerings have made him a reliable option in various game situations. His experience spanning multiple organizations has allowed him to adapt to different clubhouse environments and pitching philosophies. Leiter’s durability following his Tommy John surgery recovery has showcased his resilience and work ethic.
Notable Events and Milestones
Several significant moments define Leiter’s career trajectory. His MLB debut with the Phillies in April 2017 represented the culmination of years of development. His first career save against the Washington Nationals in August 2022 marked his emergence as a capable late-inning option. The mid-season trade to the Yankees in 2024 provided him with playoff-caliber experience. His 2023 campaign with the Cubs, where he recorded four saves while maintaining a 3.50 earned run average, stands as his most productive major league season to date.
Mark Edward Leiter Jr. Career Statistics
Across his MLB career from 2017 through 2025, Leiter has appeared in 212 games with a 16-30 win-loss record, a 4.64 earned run average, and 426 strikeouts across 286 innings pitched. His minor league performance in 2021 with the Tigers organization saw him go 10-8 with a 3.77 earned run average and 145 strikeouts in 25 appearances.
| Competition Level | G | W | L | ERA | SO | IP |
|---|---|---|---|---|---|---|
| MLB Career (2017-2025) | 212 | 16 | 30 | 4.64 | 426 | 286.0 |
Family
Family Background and Baseball Lineage
Leiter comes from a distinguished baseball family with deep roots in Major League Baseball. His father, Mark Leiter Sr., pitched for several MLB teams during his career. His uncle, Al Leiter, achieved significant success at the major league level, including a World Series championship with the Florida Marlins in 1997. Al Leiter was a two-time All-Star selection and compiled over 2,000 career strikeouts during his 19-year career.
The Leiter baseball legacy continued into the next generation with Mark Leiter Jr.’s cousin, Jack Leiter. Jack Leiter currently plays for the Texas Rangers organization and was selected in the first round of the 2021 MLB draft. This makes the Leiter family one of the rare multigenerational baseball families in professional baseball history.
Personal Life
Leiter has been a longtime resident of Lanoka Harbor, which is located in Lacey Township, New Jersey. His New Jersey roots run deep, having attended high school in the nearby Toms River area before continuing his baseball journey through the minor leagues. The family’s baseball culture undoubtedly played a role in shaping his career path from a young age.
2025 Season Performance
The 2025 season represented Leiter’s first full campaign with the New York Yankees after joining the team mid-season in 2024. He served as a reliable option out of the Yankees bullpen throughout the year, making 59 appearances and posting a 6-7 record with a 4.84 earned run average. He recorded two saves while striking out 54 batters across 48⅓ innings. The Yankees organization faced challenges during the season, but Leiter maintained consistency in his performance and availability.
His relationship with the Yankees coaching staff allowed him to contribute in various high-leverage situations throughout the season. The team relied on his experience and versatility as they navigated through the competitive American League landscape. Despite the team’s inconsistent results, Leiter’s individual contributions demonstrated his value as a bullpen asset.
Following the conclusion of the 2025 season, the Yankees made the business decision to non-tender Leiter, making him a free agent. The move opened opportunities for him to explore other organizations, ultimately leading to his signing with the Oakland Athletics in December 2025. The one-year, $2.85 million contract reflects the organization’s belief in his ability to contribute to their bullpen moving forward.