Justin Martinez Bio
Justin Martinez (born July 30, 2001) is a Dominican professional baseball pitcher for the Arizona Diamondbacks of Major League Baseball (MLB). He made his MLB debut in 2023 after signing with the Diamondbacks as an international free agent in 2018. Over the course of his early career, Martinez has shown promise despite facing challenges with injuries, recently securing a five-year contract extension with the team.
Early Life and Background
Justin Martinez was born on July 30, 2001, and grew up in the Dominican Republic, a country that has produced a steady stream of Major League Baseball talent. From a young age, he developed an interest in pitching, working on the mechanics that would later define his professional career. The specifics of his hometown, family, and formal education are not publicly documented in available sources.
Martinez’s path to professional baseball followed the well-established international route that many Dominican players use to reach the Major Leagues. His strong arm and physical projection drew the attention of scouts working for Major League organizations, and he was identified early as a prospect worth developing.
Path to Professional Baseball
On March 5, 2018, Justin Martinez signed with the Arizona Diamondbacks as an international free agent, beginning his professional career. He made his professional debut that same year with the Dominican Summer League Diamondbacks, the organization’s entry-level affiliate in his home country. The signing represented the first major step in his climb through the Minor League system.
During the 2019 season, Martinez moved between three affiliates, including the DSL Diamondbacks, the rookie-level Arizona League Diamondbacks, and the rookie-level Missoula Osprey. Across 18 games and 10 starts, he recorded a 2.89 earned run average with 78 strikeouts in 56 innings of work, demonstrating the strikeout ability that has become a hallmark of his game. His progress was halted in 2020 when the minor league season was canceled because of the COVID-19 pandemic.
Justin Martinez Career
Early Career (2018–2020)
Martinez opened his professional career with the Dominican Summer League Diamondbacks in 2018, getting his first taste of organized professional baseball in his home country. The following season, the Diamondbacks spread his development across three different affiliates, including stints in the Dominican Summer League, the Arizona League, and the rookie-level Pioneer League with the Missoula Osprey. His combined 2.89 ERA and 78 strikeouts across 56 innings signaled a pitcher with swing-and-miss potential.
The 2020 minor league season was canceled because of the COVID-19 pandemic, keeping Martinez off the mound for the entire year. Despite the lost developmental time, the Diamondbacks remained committed to his progression as a pitching prospect.
Minor League Development and Tommy John Surgery (2021–2022)
Martinez began the 2021 season with the Single-A Visalia Rawhide, but his year was cut short after only seven starts when he underwent Tommy John surgery, a common procedure for pitchers dealing with elbow injuries. The surgery forced him to miss the remainder of the 2021 season and required a lengthy rehabilitation period.
He returned to game action partway through the 2022 season, splitting his time among the rookie-level Arizona Complex League Diamondbacks, the High-A Hillsboro Hops, the Double-A Amarillo Sod Poodles, and the Triple-A Reno Aces. Across 20 games, he posted a 3.32 ERA with 62 strikeouts in 38 innings of work. After the regular season, Martinez participated in the Arizona Fall League and earned a spot in the league’s all-star game in November 2022. On November 15, 2022, the Diamondbacks added him to their 40-man roster to protect him from the Rule 5 draft.
MLB Debut and Rookie Season (2023)
Martinez was optioned to the Triple-A Reno Aces to begin the 2023 season, where he appeared in 25 games and posted a 4.18 ERA with 38 strikeouts and 5 saves in 28 innings of work. On June 27, 2023, he was promoted to the Major Leagues for the first time, though he went unused out of the bullpen and was optioned back to Reno on June 29, briefly becoming a phantom ballplayer. He was promoted for a second time on July 7, 2023, making his MLB debut the same day by allowing two runs in one inning against the Pittsburgh Pirates. Across 10 games during his rookie campaign, Martinez struggled to a 12.60 ERA with 14 strikeouts in 10 innings pitched.
Arizona Diamondbacks Era (2024–Present)
Martinez was again optioned to Triple-A Reno to begin the 2024 season, but he returned to the Major Leagues and became a reliable member of the Diamondbacks bullpen. He made 64 appearances, posting a 5-6 record with a 2.48 ERA, 91 strikeouts, and 8 saves across 72 and two-thirds innings pitched, establishing himself as a high-leverage relief option.
On March 21, 2025, Martinez and the Diamondbacks agreed to a five-year, $18 million contract extension, locking him in through the 2030 season. In 17 appearances that year, he compiled a 1-2 record and 4.11 ERA with 22 strikeouts and five saves across 15 and one-third innings pitched. On June 10, 2025, he was placed on the injured list with a right UCL sprain, and three days later, it was announced that he would undergo Tommy John surgery, ending his season.
Notable Events and Milestones
One of the defining moments of Justin Martinez’s early career came on March 21, 2025, when he agreed to a five-year, $18 million contract extension with the Arizona Diamondbacks, a clear sign of the organization’s confidence in his long-term potential. His MLB debut on July 7, 2023, against the Pittsburgh Pirates marked the culmination of his rise through the Minor League system. The 2024 season represented his first sustained Major League success, with 64 appearances, eight saves, and a 2.48 ERA that established him as a key bullpen piece. His second Tommy John surgery in 2025 represents the most significant setback of his career to date.
Justin Martinez Career Wins
Justin Martinez is primarily a relief pitcher, so his win totals reflect his role as a bullpen arm rather than a traditional starting pitcher. Across his MLB career through the 2025 season, he has compiled a 6-8 win-loss record with a 3.77 earned run average, 127 strikeouts, and 14 saves in limited innings of work. His save totals underscore his value as a late-inning reliever for the Arizona Diamondbacks.
Justin Martinez Family
Family Background and Personal Life
Justin Martinez is a native of the Dominican Republic, though specific details about his parents, siblings, and extended family are not publicly documented in available sources. Like many Dominican professional baseball players, he represents a country with a deep baseball tradition that has produced generations of Major League talent. Public information about his personal life, including any relationships or children, is not widely available at this time.
2025 Season Performance
The 2025 season began on a high note for Justin Martinez, who agreed to a five-year, $18 million contract extension with the Arizona Diamondbacks on March 21. Through his first 17 appearances of the year, he posted a 1-2 record and 4.11 ERA with 22 strikeouts and five saves across 15 and one-third innings pitched, continuing his role as a key late-inning option out of the bullpen.
His season was cut short on June 10, 2025, when he was placed on the injured list due to a right UCL sprain. Three days later, the Diamondbacks announced that Martinez would undergo Tommy John surgery, ending his 2025 campaign. The injury represents a significant setback, though his long-term contract extension suggests the organization remains committed to his recovery and future role with the team.
Looking ahead, Martinez is expected to focus on rehabilitation and a return to the Major Leagues once he has recovered from surgery. His five-year extension running through the 2030 season underscores the Diamondbacks’ belief in his long-term potential as a high-leverage reliever.
