Diamondbacks' Ace Has Injury Setback During Throwing Program

The team is calling the injury a strain of the teres major muscle in Burnes' surgically repaired throwing arm. The teres major lies in the upper arm and connects the scapula to the humerus. This area of the arm is critical for pitching, as it provides the force to drive the arm forward and generate velocity on the pitch. Before this setback, Burnes had progressed to facing live batters last week, and he and the team were optimistic for a mid-season return.

Burnes signed a six-year, $210 million deal with the Diamondbacks in December 2024 but suffered an elbow injury after just 11 starts in 2025. The former NL Cy Young Award winner was in the midst of posting another All-Star caliber season with his new team. Through those 11 starts, Burnes had a 2.66 ERA, 1.16 WHIP, and 63 strikeouts in 64.1 innings of work.

According to Piecoro, Diamondbacks manager Torey Lovullo said that the injury setback will push Burnes' return back to September at the earliest. Injuries are simply not something Burnes has had to deal with earlier in his career. Before signing his contract with Arizona, Burnes was the definition of a workhorse, throwing no fewer than 193 innings between 2022 and 2024. In 2022, Burnes compiled 202.0 innings pitched and led the majors with 33 games started and the National League with 243 strikeouts.