Rockies Reliever RJ Petit Sidelined with UCL Sprain

SCOTTSDALE, Ariz. — Colorado Rockies relief pitcher RJ Petit has been diagnosed with a sprained ulnar collateral ligament (UCL) in his right elbow, the team announced Monday. The injury indefinitely sidelines the 26-year-old right-hander.

The Rockies will conduct further testing to determine the appropriate course of treatment for Petit, according to the team’s statement.

Petit was selected by Colorado with the first pick of the 2025 Rule 5 draft from the Detroit Tigers organization. Prior to the injury, he was making a strong impression during Spring Training, with news reports highlighting his positive performance. MLB.com noted that Petit was making a “good first impression” this spring.

In 2025, Petit appeared in 47 games (two starts) across Double-A Erie and Triple-A Toledo, posting a 10-2 record with a 2.44 ERA. He struck out 79 batters and walked 22 in 66 1/3 innings pitched. Purple Row detailed his performance, noting his dominant K/9 rate at both levels.

Originally drafted by the Tigers in the 14th round of the 2021 MLB June Amateur Draft out of Charleston Southern University, Petit has a career record of 21-15 with a 3.40 ERA and 14 saves in 182 relief appearances and five starts over five minor league seasons. Baseball-Reference provides a comprehensive overview of his minor league statistics.

RJ Petit: Player Profile

Full Name: Robert George Petit Jr.
Born: September 23, 1999 (Age 26)
Height/Weight: 6’8”, 300 lbs
Throws: Right
Position: Relief Pitcher

Draft: 2021, Detroit Tigers, Round 14