Justin Martínez Bio
Justin Martínez is a Dominican professional baseball pitcher who currently plays for the Arizona Diamondbacks of Major League Baseball (MLB). Born on July 30, 2001, he signed with the Diamondbacks as an international free agent on March 5, 2018, and worked his way through the minor leagues before making his MLB debut in July 2023. Martínez has established himself as a reliable relief pitcher, compiling a career record of 6 wins and 8 losses with a 3.77 earned run average and 14 career saves through the 2025 season. In March 2025, he secured a five-year, $18 million contract extension with Arizona, demonstrating the organization’s long-term commitment to his development despite facing injury challenges throughout his early career.
Early Life and Background
Justin Martínez was born on July 30, 2001, in the Dominican Republic. While specific details about his upbringing and family background are not widely publicized, his Dominican heritage positioned him within a baseball culture that has produced numerous professional players for MLB organizations. The Dominican Republic is renowned worldwide for developing elite talent, and Martínez’s journey reflects the pathway many Dominican players follow toward professional baseball careers.
Path to Major League Baseball
Martínez signed with the Arizona Diamondbacks as an international free agent on March 5, 2018, marking his official entry into professional baseball. He made his professional debut with the Dominican Summer League Diamondbacks, beginning his development within the Diamondbacks’ international player development system. This signing represented a significant opportunity for the young pitcher to showcase his abilities within one of MLB’s organizations.
In 2019, Martínez split his season between three affiliates within the Diamondbacks’ minor league system: the DSL Diamondbacks, the rookie-level Arizona League Diamondbacks, and the rookie-level Missoula Osprey. Across 18 games (10 starts) with these three teams, he demonstrated his potential by recording a 2.89 ERA with 78 strikeouts across 56 innings of work. His performance indicated promise as a developing pitcher capable of missing bats while keeping opposing hitters off balance.
Martínez did not play in 2020 due to the cancellation of the minor league season caused by the COVID-19 pandemic, which interrupted the development of many young players across professional baseball. The following year, he began the 2021 season with the Single-A Visalia Rawhide but suffered a significant setback, undergoing Tommy John surgery after making only 7 starts. This elbow reconstruction procedure typically requires a recovery timeline of 12 to 18 months, placing his career trajectory temporarily on hold.
Justin Martínez Career
Minor League Recovery and Return (2022)
Martínez returned to competition in 2022, partway through the season following his Tommy John rehabilitation. He appeared in 20 games across four levels of the minor leagues: the rookie-level Arizona Complex League Diamondbacks, High-A Hillsboro Hops, Double-A Amarillo Sod Poodles, and Triple-A Reno Aces. His cumulative performance across these affiliates yielded a 3.32 ERA with 62 strikeouts in 38 innings pitched. This steady progression through multiple levels demonstrated his ability to recover effectively from major surgery and advance his career.
After the 2022 regular season, Martínez continued his development by playing in the Arizona Fall League, an offseason instructional league featuring top minor league prospects. His strong performance earned him a selection to the league’s All-Star Game in November, a notable accomplishment that highlighted his recovery and potential. On November 15, 2022, the Diamondbacks added Martínez to their 40-man roster, protecting him from the Rule 5 draft and signaling their confidence in his future contributions.
MLB Debut and 2023 Season
Martínez began the 2023 season with the Triple-A Reno Aces, Arizona’s top minor league affiliate. In 25 games for Reno, he posted a 4.18 ERA with 38 strikeouts and converted 5 saves in 28 innings of work. His solid performance at the Triple-A level earned him a promotion to the major leagues. On June 27, 2023, Martínez was called up to the Arizona Diamondbacks for the first time. He went unused out of the bullpen and was optioned back to Reno on June 29, becoming what is known as a phantom ballplayer.
Martínez received a second promotion on July 7, 2023, and made his MLB debut that same day against the Pittsburgh Pirates. In his debut appearance, he pitched one inning and allowed two runs. Overall during his rookie campaign, Martínez appeared in 10 games and struggled to a 12.60 ERA with 14 strikeouts across 10 innings pitched. The difficult introduction to major league competition is not uncommon for young pitchers making the jump from Triple-A, and the experience provided valuable learning opportunities for his continued development.
Breakthrough 2024 Season
Martínez returned to Triple-A Reno to begin the 2024 season, continuing to refine his craft at the highest minor league level. He earned another promotion to the majors during the year and became a key contributor to the Diamondbacks’ bullpen. In 64 appearances for Arizona during the 2024 season, Martínez delivered a strong performance that represented a significant breakthrough in his career.
He posted a 5-6 win-loss record with a 2.48 ERA, one of the best marks among Diamondbacks relievers. Martínez recorded 91 strikeouts and converted 8 saves across 72 and two-thirds innings pitched, establishing himself as a reliable option in late-game situations. His breakout season demonstrated the potential the Diamondbacks saw when they signed him in 2018 and protected him on their 40-man roster just two years prior.
2025 Season and Contract Extension
On March 21, 2025, Martínez and the Diamondbacks agreed to a five-year, $18 million contract extension running through the 2030 season. This deal represented a substantial commitment from the organization and reflected their belief in his long-term value to the club. The extension provided Martínez with financial security while allowing the Diamondbacks to maintain control of a promising young pitcher.
Through early June 2025, Martínez made 17 appearances for the Diamondbacks, compiling a 1-2 record with a 4.11 ERA and 22 strikeouts across 15 and one-third innings. He also recorded 5 saves during this span. However, his season encountered a major obstacle on June 10, 2025, when he was placed on the injured list due to a right ulnar collateral ligament (UCL) sprain. Three days later, it was announced that Martínez would undergo Tommy John surgery, effectively ending his 2025 season. This marked the second time in his career he has required the procedure, as he previously underwent the surgery in 2021.
Pitching Style and Strengths
Martínez has developed into a capable relief pitcher with the ability to record outs in high-leverage situations. His strikeout ability, demonstrated by his 127 career punchouts through 2025, indicates a pitcher who can miss bats when needed. His experience pitching across multiple minor league levels, including a successful stint in the Arizona Fall League, has helped him develop the consistency required for major league success.
Notable Career Milestones
Several key moments stand out in Martínez’s early career trajectory. His selection to the Arizona Fall League All-Star Game in November 2022 marked him as one of the top prospects in the sport’s development system. His addition to the Diamondbacks’ 40-man roster later that same month represented the organization’s official recognition of his potential. The five-year, $18 million extension in March 2025 further cemented his place in Arizona’s future plans. Unfortunately, his second Tommy John surgery in June 2025 became a significant chapter in his career, requiring another extended rehabilitation period.
Justin Martínez Career Statistics
Through the 2025 season, Martínez has appeared in 91 major league games, all with the Arizona Diamondbacks. He has established himself as a versatile bullpen arm capable of handling various late-inning situations. His career totals include 6 wins, 8 losses, and 14 saves with a 3.77 earned run average and 127 strikeouts across 97 and one-third innings pitched. The 2024 season represents his most productive year at the major league level, while the 2025 campaign was cut short by injury.
Minor League Career Highlights
Prior to his MLB career, Martínez performed well across the Diamondbacks’ minor league system. His 2019 season across three affiliates produced a 2.89 ERA with 78 strikeouts in 56 innings, showcasing his ability to dominate at lower levels. After returning from his first Tommy John surgery in 2022, he posted a 3.32 ERA with 62 strikeouts in 38 innings across four minor league levels. His Triple-A Reno statistics in 2023 (4.18 ERA, 38 strikeouts, 5 saves in 28 innings) demonstrated his readiness for the majors before his first promotion.
Justin Martínez Family
Public information regarding Justin Martínez’s family background, parents, or siblings is not widely available. The pitcher maintains a relatively private personal life, with limited details shared publicly about his family situation. This privacy is common among professional athletes, particularly those in the early stages of their careers.
Personal Life
Martínez continues his professional baseball career while residing in the Dominican Republic and with his MLB team in Arizona during the season. He maintains an active presence on Instagram under the handle @justinmartinez63_, where he shares glimpses of his baseball career and personal life with his followers. As a young player navigating the early stages of his MLB career, Martínez focuses on his development and recovery while building his legacy with the Diamondbacks organization.
2025 Season Performance
The 2025 season began on a promising note for Martínez following his breakout 2024 campaign. The five-year contract extension announced in March demonstrated the organization’s confidence in his abilities and their desire to build around his talents. Through his first 17 appearances, he showed flashes of his previous year’s form, recording 5 saves while maintaining a 4.11 ERA. The early-season performance suggested he could be a key component of Arizona’s bullpen architecture.
However, the season took a dramatic turn when Martínez’s right elbow began causing concern. The placement on the injured list on June 10 and subsequent Tommy John surgery on June 13 ended his season prematurely. This injury represents a significant challenge for the young pitcher, requiring another lengthy rehabilitation process that will likely keep him off the mound for the majority of the 2026 season as well. The Diamondbacks remain committed to Martínez’s long-term development, as evidenced by their extension, but his return timeline will depend on his recovery from the procedure.
The silver lining for Martínez and the organization lies in his youth and the security provided by his contract extension. At 23 years old (born July 30, 2001), he has time to recover and return to form. The Diamondbacks’ investment in him reflects their belief that he can overcome this setback and contribute to their bullpen in the years ahead. Martínez’s mental resilience will be tested as he works through his second major elbow surgery, but his track record of returning from Tommy John surgery in 2021 provides a template for his recovery journey.