Justin Slaten Bio
Justin Michael Slaten, born September 15, 1997, is an American professional baseball pitcher for the Boston Red Sox of Major League Baseball (MLB). A right-handed reliever who relies on a heavy fastball, Slaten emerged from the Texas Rangers minor league system before joining Boston through the 2023 Rule 5 draft. He made his MLB debut on March 30, 2024, and quickly established himself as a reliable late-inning arm for the Red Sox bullpen during his rookie campaign.
Early Life and Background
Justin Michael Slaten was born on September 15, 1997, and grew up in the East Texas community of Hallsville. He attended Hallsville High School, where he developed into a hard-throwing pitcher under the school’s baseball program. As a senior, Slaten posted a 6–5 record with a 1.49 earned run average (ERA) and 105 strikeouts across 75 innings pitched, a workload that showcased both his durability and his ability to miss bats at the high school level.
Despite that productive final season, Slaten went undrafted out of high school, leaving him to weigh his options between professional baseball and college. He chose to pursue a college education and continue developing his craft, enrolling at The University of New Mexico to play college baseball for the New Mexico Lobos. The decision gave him additional time to refine his mechanics and add strength before entering the professional ranks.
Path to Baseball
Slaten’s college path was uneven at first, mirroring the typical adjustment curve for a young pitcher learning to handle a full college schedule. In his 2017 freshman season at New Mexico, he went 2–2 with a 3.71 ERA and 27 strikeouts across 33 and two-thirds innings. His sophomore year was a struggle, as he fell to a 2–9 record with a 7.02 ERA over 66 and two-thirds innings, prompting questions about his long-term projection.
The summer of 2018 proved to be a turning point. Slaten joined the Eau Claire Express of the Northwoods League, a respected collegiate summer circuit, and went 7–1 with a 1.58 ERA and 70 strikeouts over 57 innings, restoring confidence in his arm. He carried that momentum into his junior season in 2019, finishing 5–5 with a 2.51 ERA and 98 strikeouts across 82 and one-third innings. The strong junior year put him back on professional scouting radars and set the stage for the 2019 MLB draft.
Justin Slaten Career
Early Career (2019–2021)
The Texas Rangers selected Slaten in the third round of the 2019 MLB draft, and he signed with the organization. He split his professional debut between the AZL Rangers of the Rookie-level Arizona League and the Spokane Indians of the Low-A Northwest League, going a combined 0–2 with a 6.06 ERA and 22 strikeouts over 16 and one-third innings. Slaten did not appear in a game in 2020 after the minor league season was canceled because of the COVID-19 pandemic, delaying his on-field development by a full year.
In 2021, Slaten returned to competition with the Hickory Crawdads of the High-A East. He posted a 4–8 record with a 6.01 ERA and 110 strikeouts across 82 and one-third innings, showing swing-and-miss stuff but also the inconsistency that often comes with refining a pitcher’s arsenal at the High-A level.
Texas Rangers Minor League Development (2022–2023)
Slaten spent the 2022 season with the Frisco RoughRiders of the Double-A Texas League. He went 1–6 with a 6.93 ERA and 64 strikeouts across 50 and two-thirds innings, a difficult year that tested his resolve as a pitching prospect within the Rangers system.
Slaten returned to Frisco to open the 2023 season and broke out, going 4–3 with a 3.16 ERA and 76 strikeouts across 51 and one-third innings. His performance earned a promotion in September to the Round Rock Express of the Triple-A Pacific Coast League, where he posted a 1–0 record with a 1.08 ERA over 8 and one-third innings. Following the season, Slaten pitched for the Surprise Saguaros of the Arizona Fall League, continuing to build momentum heading into the offseason.
Boston Red Sox Era (2023–Present)
On December 6, 2023, the New York Mets selected Slaten with the seventh pick in the Rule 5 draft and promptly traded him to the Boston Red Sox in exchange for minor league left-handed pitcher Ryan Ammons and cash considerations. The Rule 5 route required Boston to keep Slaten on its major league roster, and the Red Sox added him to their Opening Day roster. Slaten made his MLB debut on March 30, 2024, beginning what became an impactful rookie season in the Red Sox bullpen.
In 44 appearances for Boston during his rookie campaign, Slaten compiled a 6–2 record and 2.93 ERA with 58 strikeouts and two saves across 55 and one-third innings pitched. He opened the 2025 season with 24 appearances for Boston, posting a 1–4 record and 3.47 ERA with 16 strikeouts and three saves across 23 and one-third innings pitched. On June 1, 2025, Slaten was placed on the injured list due to shoulder inflammation, was transferred to the 60-day injured list on June 28, and was activated on August 28.
Notable Events and Milestones
Slaten’s Rule 5 selection and subsequent trade to Boston in December 2023 stand as the defining transactions of his career, forcing an immediate jump from Triple-A to the major league roster. He responded by posting a sub-3.00 ERA as a rookie and securing two saves, validating the Red Sox’s decision to keep him in the majors for the full 2024 season.
Justin Slaten Career Wins
Slaten’s career wins are concentrated in his major league tenure with the Boston Red Sox, where he has served primarily as a reliever. His Rule 5 background limited his major league opportunities to Boston, and his early professional win totals in the Rangers system were modest.
MLB Highlights
Slaten recorded 6 wins during his rookie MLB season with the Red Sox in 2024, pairing them with a 2.93 ERA, 58 strikeouts, and two saves across 44 appearances and 55 and one-third innings. His first major league decision and first save both came during that rookie campaign, which established him as a trusted option out of the Boston bullpen. In 2025, he added three saves before a shoulder issue sidelined him from early June through late August.
Justin Slaten Family
Personal Life
Slaten’s personal life is kept largely private, and no spouse, children, or public family details are confirmed beyond his East Texas roots. He attended Hallsville High School in Hallsville, Texas, before going on to pitch collegiately at The University of New Mexico.
2025 Season Performance
Slaten entered 2025 as a key late-inning option for the Red Sox following a strong rookie campaign. Through his first 24 appearances, he recorded a 1–4 record and 3.47 ERA with 16 strikeouts and three saves across 23 and one-third innings, maintaining a role in leverage situations out of the Boston bullpen.
His season was interrupted on June 1, 2025, when shoulder inflammation landed him on the injured list, and the Red Sox transferred him to the 60-day injured list on June 28, signaling an extended absence. The Red Sox activated Slaten on August 28, 2025, returning him to the active roster with the regular season winding down and a postseason push under way.
Coming out of the injured list, Slaten’s outlook centered on reclaiming a high-leverage relief role and providing stability for a Red Sox bullpen chasing a playoff spot. His prior major league track record and his Rule 5 pedigree suggest continued opportunity in Boston’s relief corps once he regains full strength.