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). The Texas native began his baseball journey in East Texas before developing into a steady relief arm in the Boston bullpen. After several years in the minor leagues, Slaten reached the majors in 2024 and quickly earned a role out of the Red Sox bullpen. He wears jersey number 63 for Boston.
Early Life and Background
Justin Michael Slaten was born on September 15, 1997, and grew up in the Hallsville area of East Texas. He attended Hallsville High School, where he developed into one of the more polished arms in the region. As a senior, Slaten posted a 6–5 record with a 1.49 earned run average and 105 strikeouts across 75 innings, numbers that reflected both his power stuff and his growing consistency on the mound.
Despite those senior-year numbers, Slaten went undrafted out of high school, which pushed him toward the college route. He chose to attend The University of New Mexico, where he played college baseball for the New Mexico Lobos. Those three seasons in Albuquerque helped him rebuild his draft profile and gave him the innings he needed to refine his command and his breaking ball.
Path to Baseball
Slaten’s path to professional baseball was uneven but instructive. In his freshman season of 2017 with the Lobos, he went 2–2 with a 3.71 ERA and 27 strikeouts over 33 2/3 innings, showing flashes of the arm the Rangers would later target. He struggled in his sophomore year of 2018, finishing 2–9 with a 7.02 ERA across 66 2/3 innings, a season that tested his confidence but also clarified the adjustments he needed to make.
The summer of 2018 became a turning point. Slaten played for the Eau Claire Express of the Northwoods League and went 7–1 with a 1.58 ERA and 70 strikeouts over 57 innings, a dominant stretch that restored his prospect stock. In his junior year of 2019, he went 5–5 with a 2.51 ERA and 98 strikeouts over 82 1/3 innings, putting him firmly back on professional scouts’ radar.
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 1/3 innings. Slaten did not appear in a game in 2020 after the minor league season was canceled because of the COVID-19 pandemic, which cost him a full year of development.
He returned in 2021 with the Hickory Crawdads of the High-A East, where he went 4–8 with a 6.01 ERA and 110 strikeouts over 82 1/3 innings. The high strikeout totals were encouraging, even as the win-loss record reflected the offensive environment around him.
Texas Rangers (2022–2023)
Slaten spent the 2022 season with the Frisco RoughRiders of the Double-A Texas League, going 1–6 with a 6.93 ERA and 64 strikeouts over 50 2/3 innings. He returned to Frisco to open 2023 and broke out, going 4–3 with a 3.16 ERA and 76 strikeouts across 51 1/3 innings. That performance earned him a September promotion to the Round Rock Express of the Triple-A Pacific Coast League, where he posted a 1–0 record and a 1.08 ERA over 8 1/3 innings. Following the 2023 season, Slaten joined the Surprise Saguaros of the Arizona Fall League, a traditional finishing school for top prospects.
Boston Red Sox Era (2024–Present)
On December 6, 2023, the New York Mets selected Slaten with the seventh overall pick in the Rule 5 draft, then traded him to the Boston Red Sox for minor league left-hander Ryan Ammons and cash considerations. Boston added him to its Opening Day roster, and Slaten made his major league debut on March 30, 2024. In 44 appearances during his rookie campaign, he went 6–2 with a 2.93 ERA, 58 strikeouts, and two saves across 55 1/3 innings, locking down a middle-relief role almost immediately.
Driving Style and Strengths
Slaten has built his role on a power fastball paired with a sharp breaking ball, the kind of swing-and-miss combination that plays well in late-inning relief. His strikeout totals at every level, from college through Triple-A and into the majors, point to swing-and-miss stuff rather than soft contact, and his 2024 ERA showed he could miss bats and limit damage in the same outing.
Notable Events and Milestones
Slaten’s most notable milestone came on December 6, 2023, when he was selected in the Rule 5 draft and quickly traded to Boston, the move that put him on a major league mound for the first time. His March 30, 2024 debut marked the culmination of a five-year climb through professional baseball, and his strong rookie season established him as a fixture in the Red Sox bullpen.
Justin Slaten Career Stats
Justin Slaten has compiled a credible body of work across the Rangers’ minor league system and the Boston Red Sox bullpen, with his major league numbers coming in 2024 and 2025. Through his first full major league stretch, he has shown a steady ERA, dependable strikeout totals, and the kind of usage pattern that suggests the Red Sox view him as a long-term relief piece.
MLB Highlights
Slaten’s first major league season in 2024 was the foundation: a 6–2 record, a 2.93 ERA, 58 strikeouts, and two saves across 55 1/3 innings in 44 appearances. Those numbers, combined with a spot on Boston’s Opening Day roster, set a strong tone for what the Red Sox hoped would be a long career at the back end of their bullpen.
Justin Slaten Family
Family Background and Personal Life
Slaten grew up in the Hallsville area of East Texas and attended Hallsville High School before continuing his baseball career at The University of New Mexico. Detailed information about his parents, siblings, and broader family background has not been widely published. Publicly available details about his personal life remain limited beyond his career and his education.
2025 Season Performance
Slaten opened the 2025 season in a familiar role out of the Boston bullpen, making 24 appearances before the calendar turned to summer. He posted a 1–4 record with a 3.47 ERA, 16 strikeouts, and three saves across 23 1/3 innings pitched, showing the same swing-and-miss profile that defined his rookie year. His save totals in that stretch suggested the Red Sox were comfortable using him in higher-leverage spots.
On June 1, 2025, Boston placed Slaten on the injured list due to shoulder inflammation, and on June 28 the team transferred him to the 60-day injured list, a longer window that pointed to a more cautious recovery plan. He was activated on August 28 and returned to a bullpen that had been managing without him through the heart of summer. Looking ahead, Slaten’s role with the Red Sox going into 2025 and beyond is expected to remain in late relief, where his strikeout ability and prior big-league results give Boston a trusted option in tight spots.