Martinez experienced tightness in his elbow during a game against the Seattle Mariners on June 9, 2025, which led to his exit after striking out two batters.

An MRI conducted shortly after revealed the UCL sprain, resulting in his placement on the injured list on June 10, 2025.

Earlier this season, Martinez had already been on the 15-day injured list due to right shoulder inflammation before returning to action.

At just 23 years old, Martinez transitioned to a relief role following Tommy John surgery in 2021, and has recorded a season record of 1-2 with five saves and a 4.11 ERA in 17 appearances.

The Diamondbacks are prioritizing Martinez's long-term health by ensuring he does not rush back, aiming to preserve him as a high-leverage reliever for the future.

Arizona Diamondbacks reliever Justin Martinez is set to miss 12 to 13 months due to a sprained right ulnar collateral ligament (UCL) in his throwing elbow, as confirmed by manager Torey Lovullo.

The team is currently facing challenges with depth, as they have eight pitchers on the injured list, including Cristian Mena, Kendall Graveman, and Christian Montes De Oca, who also lack a timetable for return.

Among those injured, four pitchers, including Martinez, are out for the season due to UCL injuries, highlighting a significant challenge for the team's pitching staff.

Despite mixed reactions from fans regarding the severity of Martinez's injury, the Diamondbacks maintain that the lengthy recovery period is a cautious decision aimed at ensuring his future performance.

Fan reactions have been varied, with some expressing skepticism about the injury's severity and comparing it to other players like Bryce Harper, who played through similar UCL issues.

Manager Lovullo noted that the term 'sprain' can be misleading, emphasizing the need for a careful approach to Martinez's recovery due to the internal strain on his UCL.

As a result of Martinez's absence, the Diamondbacks will need to explore alternative bullpen options for the remainder of the 2025 MLB season.