Aaron Bummer Bio
Aaron James Bummer, born on September 21, 1993, is an American professional baseball pitcher who has built his career as a dependable left-handed reliever in Major League Baseball (MLB). After rising through the Chicago White Sox system and developing into one of the most trusted bullpen arms in the American League, Bummer was traded to the Atlanta Braves in November 2023, beginning a new chapter of his career. Known for his heavy sinker and ability to induce ground balls, he has been a steady presence in high-leverage relief situations throughout his big-league tenure. He currently plays in the Chicago Cubs organization after being released by the Braves in May 2026.
Early Life and Background
Aaron James Bummer was born on September 21, 1993, and grew up in the Peoria, Arizona area, where he attended Sunrise Mountain High School. He played for the school’s baseball team and developed into a promising left-handed pitcher during his high school years. As a young prospect, Bummer caught the attention of professional scouts and was selected by the New York Yankees in the 31st round of the 2011 MLB draft.
Rather than begin his professional career right away, Bummer chose to continue his education and play college baseball. He enrolled at the University of Nebraska–Lincoln, where he spent three seasons pitching for the Nebraska Cornhuskers. In the summer of 2013, he played collegiate summer baseball with the Harwich Mariners of the Cape Cod Baseball League and was named a league all-star. As a junior in 2014, Bummer posted a 7–5 win–loss record with a 3.34 earned run average (ERA) in 15 games started, establishing himself as one of the more polished college arms heading into that year’s draft.
Path to MLB
Bummer’s professional journey officially began in 2014 when the Chicago White Sox selected him in the 19th round, with the 558th overall pick, of the MLB draft. After signing, he made his professional debut that same year with the Great Falls Voyagers, where he posted a 2.45 ERA across 22 innings pitched. He then missed the entire 2015 season due to injury, an early setback that tested his commitment to the sport.
In 2016, Bummer bounced back and pitched for the Arizona League White Sox, Great Falls, and Winston-Salem Dash, combining to go 1–2 with a 4.86 ERA in 15 relief appearances. He opened 2017 with Winston-Salem, was promoted to the Birmingham Barons in May, and reached the Charlotte Knights in July. After compiling a 3.31 ERA in 49 innings across the three minor league levels, Bummer earned his call to the majors, and the White Sox selected his contract on July 27, 2017, leading to an MLB debut that same night against the Chicago Cubs.
Aaron Bummer Career
Early Career (2017–2018)
Bummer made an immediate impression in his MLB debut on July 27, 2017, striking out the first batter he faced, Anthony Rizzo of the Cubs. He spent the remainder of the 2017 season in the White Sox bullpen, going 1–3 with a 4.50 ERA in 30 relief appearances. The following year, in 2018, he appeared in 37 games and posted a 4.26 ERA across 31 and two-thirds innings, gradually earning the trust of the Chicago coaching staff as a reliable left-handed option out of the bullpen.
Chicago White Sox Breakthrough (2019–2022)
The 2019 season marked a true breakout for Bummer. He made 58 appearances and registered a stellar 2.13 ERA over 67 and one-third innings while striking out 60 batters, cementing his role as a high-leverage reliever. The White Sox rewarded his performance with a five-year, $16 million contract, signaling their confidence in his long-term future with the club.
His momentum was briefly halted in 2020, when a left biceps strain limited him to just nine regular-season games. He returned for the final week of the year and appeared in two games of the American League Wild Card Series against the Oakland Athletics, allowing no runs in one and one-third innings of work. In 2021, Bummer appeared in 62 games, posted a 3.51 ERA across 56.1 innings, and struck out 75 batters as the White Sox returned to the postseason, where he made three appearances in the American League Division Series against the Houston Astros. He followed that with a 2022 campaign in which a knee injury cost him three months, yet he still managed a strong 2.36 ERA in 26 and two-thirds innings across 32 outings.
Atlanta Braves Era (2023–2026)
On November 16, 2023, the White Sox traded Bummer to the Atlanta Braves in exchange for Michael Soroka, Jared Shuster, Nicky Lopez, Braden Shewmake, and Riley Gowens. In November 2024, the two sides agreed to a restructured contract that guaranteed him $3.5 million for the 2025 season and $9.5 million in 2026. That summer, on July 5, 2025, Bummer made his first career start after 374 relief appearances, facing the Baltimore Orioles, where he set a personal record by striking out the first five batters he faced before ultimately exiting in the third inning. He finished 2025 with a 3–2 record and 3.81 ERA across 42 appearances and 54 and one-third innings, but a left shoulder inflammation issue placed him on the injured list in late August and ended his season.
Driving Style and Strengths
Bummer is widely recognized for his heavy sinker, a pitch he uses to generate ground balls and weak contact rather than swing-and-miss strikeouts. His ability to work quickly, attack left-handed hitters, and avoid walks has made him a trusted bridge to the late innings. Throughout his career, his effectiveness has come from command, deception, and a willingness to pitch to contact in high-pressure moments.
Notable Events and Milestones
Bummer’s most memorable MLB moment came on debut night, when he struck out Anthony Rizzo, the Cubs’ star slugger, on his very first big-league pitch. His 2019 breakout, his first career start in 2025, and his run of consecutive scoreless postseason innings against Oakland in 2020 also stand out as defining milestones in his professional journey.
Aaron Bummer Career Highlights
Across his MLB career, Aaron James Bummer has established himself as a durable and effective relief pitcher, appearing in more than 350 regular-season games. His best statistical season came in 2019, when he posted a 2.13 ERA over 67 and one-third innings for the White Sox. He has also made multiple postseason appearances, including work in both the 2020 Wild Card Series and the 2021 American League Division Series.
Aaron Bummer Family
Personal Life
Aaron James Bummer earned his bachelor’s degree in finance from the University of Nebraska–Lincoln in December 2016. He married his wife, Amber, in 2018, and the couple welcomed their first child, a daughter, in February 2021.
2025 Season Performance
The 2025 season marked a new chapter for Aaron James Bummer with the Atlanta Braves, as he transitioned from his familiar relief role into a broader usage pattern that included starting assignments. On July 5, 2025, he made his first career start against the Baltimore Orioles, striking out the first five batters he faced before exiting in the third inning. Across 42 appearances, including two starts, Bummer compiled a 3–2 record with a 3.81 ERA and 51 strikeouts over 54 and one-third innings, demonstrating continued value out of the bullpen even as he expanded his role.
His 2025 campaign, however, was cut short by a left shoulder inflammation issue that landed him on the injured list on August 24, before being transferred to the 60-day injured list on September 18, officially ending his season. Heading into 2026, Bummer remained under contract with the Braves, and the restructured deal offered both club and player a clear framework for the coming year.
