Geoffrey Thomas Hartlieb Bio
Geoffrey Thomas Hartlieb is an American professional baseball pitcher who currently plays for the Oakland Athletics in Major League Baseball. Born on December 9, 1993, in Highland, Illinois, Hartlieb has built a career spanning multiple MLB organizations since being drafted in 2016. His journey through professional baseball includes stops with the Pittsburgh Pirates, New York Mets, Miami Marlins, Colorado Rockies, New York Yankees, and Detroit Tigers before joining the Athletics. Known as a versatile reliever, Hartlieb has appeared in games across multiple seasons while steadily developing his craft in minor league systems.
Early Life and Background
Hartlieb grew up in Highland, Illinois, where he attended Highland High School. During his high school years, he was a standout athlete, earning all-state honors in basketball during both his junior and senior years. Interestingly, Hartlieb originally quit baseball at the end of high school, choosing to focus his athletic energy on basketball before eventually returning to the diamond at the collegiate level.
After graduating from Highland High School, Hartlieb enrolled at Quincy University in Quincy, Illinois, in 2013. He spent his freshman year of college playing basketball for the Quincy Hawks. Seeking a change in direction, he transferred to Lindenwood University in Saint Charles, Missouri, where he played college baseball from 2014 through 2016. His performance at Lindenwood caught the attention of professional scouts and set the stage for his future baseball career.
Path to Professional Baseball
Hartlieb’s path to professional baseball included an early draft experience that nearly launched his career before he was fully ready. The New York Mets selected him in the 37th round of the 2015 Major League Baseball draft, but Hartlieb did not sign and returned to Lindenwood for his final year of collegiate play. This decision proved beneficial, as it allowed him to further develop his skills and increase his draft stock.
Following his collegiate career at Lindenwood, Hartlieb entered the 2016 MLB draft. This time, he was selected by the Pittsburgh Pirates in the 29th round. He signed with the organization and began his professional career that same year, embarking on the development journey through the minor leagues that would eventually lead him to the majors.
Geoffrey Thomas Hartlieb Career
Minor League Development (2016–2019)
Hartlieb began his professional career in 2016 with the Bristol Pirates, the Pirates’ Appalachian League affiliate. He posted a strong first season, going 4–1 with a 4.44 earned run average in 26 innings pitched. This solid beginning established him as a promising prospect within Pittsburgh’s farm system.
In 2017, Hartlieb split the season between the West Virginia Power and the Bradenton Marauders. He combined to go 2–6 with an impressive 2.12 earned run average across 63 and two-thirds innings pitched, demonstrating his ability to miss bats and keep opposing hitters off balance. The following year, 2018, he played for the Altoona Curve, the Pirates’ Double-A affiliate, where he thrived with an 8–2 record and a 3.24 earned run average in 58 innings pitched. During the 2018 offseason, Hartlieb gained additional experience playing for the Surprise Saguaros of the Arizona Fall League, a prestigious league that features top prospects from across all MLB organizations.
Pittsburgh Pirates (2019–2021)
The Pirates promoted Hartlieb to the major leagues for the first time on May 17, 2019, and he made his MLB debut the following day against the San Diego Padres. This promotion represented the culmination of his steady climb through the minor leagues and the realization of his childhood dream. Throughout his rookie season, Hartlieb appeared in multiple games for Pittsburgh, adjusting to the highest level of competition in professional baseball.
In the shortened 2020 season, Hartlieb emerged as a reliable option in the Pirates’ bullpen. He pitched to a 3.63 earned run average, allowing only one home run in 22 and one-third innings pitched. His ability to limit home runs and maintain composure on the mound showcased his potential as a durable reliever at the major league level. However, the 2021 season presented challenges as Hartlieb split time between Triple-A Indianapolis and Pittsburgh. He struggled in his limited major league appearances, posting a 7.71 earned run average in four games before the Pirates designated him for assignment on July 3, 2021.
New York Mets (2021)
On July 9, 2021, Hartlieb was claimed off waivers by the New York Mets and assigned to the Triple-A Syracuse Mets. He made seven appearances for the Mets that season but faced difficulties adjusting to his new organization, posting an 11.00 earned run average with nine strikeouts. The Mets designated Hartlieb for assignment on September 2, 2021, bringing his brief tenure with the club to an end.
Miami Marlins (2023)
After spending the 2022 season entirely with Triple-A Worcester in the Boston Red Sox organization, Hartlieb signed a minor league deal with the Miami Marlins on November 29, 2022. In 2023, he began the season with the Triple-A Jacksonville Jumbo Shrimp, where he performed well with a 3.18 earned run average, 36 strikeouts, and six saves in 34 innings pitched across 26 games. His strong minor league performance earned him a call-up when the Marlins selected his contract on August 6, 2023. Hartlieb made his Miami debut that same day, tossing one inning against the Texas Rangers and allowing one run while striking out two. He made only two total appearances for the Marlins before being designated for assignment on September 6, 2023.
Colorado Rockies (2024)
Hartlieb signed another minor league contract with the Colorado Rockies on November 13, 2023. He opened the 2024 season with the Triple-A Albuquerque Isotopes, where he logged a 5.61 earned run average with 34 strikeouts in 33 and two-thirds innings across 22 games. The Rockies selected his contract and added him to their active roster on June 8, 2024. Hartlieb appeared in five games for Colorado, but struggled with a 9.00 earned run average and seven strikeouts in nine innings. The Rockies designated him for assignment following a roster move on June 22, and he cleared waivers, being sent outright to Albuquerque on June 25.
New York Yankees (2025)
On October 18, 2024, Hartlieb signed a minor league contract with the New York Yankees. He reported to the Triple-A Scranton/Wilkes-Barre RailRiders and performed admirably, posting a 3-2 record with a 3.34 earned run average, 38 strikeouts, and two saves in 35 innings across 24 appearances. The Yankees selected his contract on June 30, 2025, adding him to their major league roster. Hartlieb made his Yankees debut on July 1 against the Toronto Blue Jays, allowing three runs in one inning of work. He was designated for assignment the following day. Hartlieb elected free agency on July 4 rather than accept an outright assignment, but he re-signed with New York on a major league contract on July 6. He made one more appearance before being designated for assignment again on July 9 and electing free agency on July 11.
Detroit Tigers (2025)
Hartlieb joined the Detroit Tigers organization on July 12, 2025, signing a minor league contract. He reported to the Triple-A Toledo Mud Hens and made two scoreless appearances, recording one win, four strikeouts, and one save across four and one-third innings. The Tigers selected his contract on July 24, adding him to their major league roster. However, Hartlieb appeared in only two games for Detroit before being designated for assignment on July 26. He cleared waivers and elected free agency on July 30, then re-signed with the Tigers organization on a minor league contract the following day. He was released on August 19, 2025.
Oakland Athletics (2026–Present)
Following his release from Detroit, Hartlieb signed with the Oakland Athletics organization on November 20, 2025. He joined an Athletics team that has been rebuilding and providing opportunities to veteran players seeking to contribute at the major league level. Hartlieb brings experience from his multiple MLB organizations and a track record of solid minor league performance that could earn him another opportunity with the Athletics during the 2026 season.
Throwing Style and Strengths
Hartlieb operates primarily as a relief pitcher, utilizing his low-to-mid-90s fastball to generate ground balls and strikeouts. Throughout his career, he has shown the ability to pitch effectively in multiple innings of relief, handling high-pressure situations with composure. His experience across various minor league levels and multiple major league organizations demonstrates his adaptability and durability as a professional pitcher.
Notable Career Statistics
Through June 25, 2026, Hartlieb has compiled a career major league record of 2–1 with a 7.60 earned run average and 83 strikeouts across his appearances. While his major league opportunities have been limited, his consistent performance in Triple-A leagues, including multiple seasons with earned run averages under 5.50, demonstrates his ability to compete at the highest level when given the chance.
Geoffrey Thomas Hartlieb Career Highlights
Hartlieb’s career has been characterized by resilience and adaptability, as he has navigated through multiple organizations while maintaining strong minor league numbers. His best major league season came in 2020 with Pittsburgh, when he posted a 3.63 earned run average in 22 and one-third innings during the shortened season.
Professional Career Statistics
| Level | Years | W-L Record | ERA | |
|---|---|---|---|---|
| MLB Career | 2019–2025 | 2–1 | 7.60 | 83 |
| Triple-A Career | 2019–2025 | Multiple seasons | 3.18–5.61 | Multiple seasons |
Other Notable Performances
Hartlieb’s standout minor league season came in 2018 with Double-A Altoona, where he went 8–2 with a 3.24 earned run average in 58 innings, earning consideration as one of Pittsburgh’s top relief prospects. His 2017 season with Bradenton also showcased his potential, as he posted a remarkable 2.12 earned run average across 63 and two-thirds innings between two affiliates.
Family
Background
Limited information is publicly available regarding Hartlieb’s family background. He was born and raised in Highland, Illinois, where he attended local schools and developed his athletic abilities. His parents supported his early interests in basketball and baseball, with Hartlieb’s mother and father providing the foundation for his pursuit of collegiate athletics.
Personal Life
Hartlieb is married to his wife, Brooke Hartlieb. The couple has been together throughout his professional baseball career, supporting his journey through multiple organizations and relocations across the country. Hartlieb maintains connections to his Illinois roots while adapting to life as a professional athlete.
2025 Season Review
The 2025 season represented another year of transition for Hartlieb as he continued his journey through major league organizations. He began the year with the New York Yankees’ Triple-A affiliate in Scranton/Wilkes-Barre, where he performed well enough to earn a mid-season call-up to the Bronx. His lone appearance with the Yankees on July 1 against Toronto proved challenging, as he allowed three runs in one inning of work. The quick departure from New York led him to sign with Detroit, where he appeared in two major league games before the end of July. Following his release from the Tigers, Hartlieb signed with Kansas City and finished the season with Omaha before ultimately joining the Oakland Athletics organization in November.