Rockies starting pitcher Tyler Chatwood will undergo season-ending Tommy John surgery on his pitching elbow, according to a report in The Denver Post.
The club has not confirmed the news regarding the right-hander, who has been on the disabled list since April 30 with a right flexor tendon strain. He left his start the previous night against the D-backs after five innings due to tightness in the elbow.
Chatwood had since dealt with a setback and the 24-year-old already is on the 60-day DL. Tommy John surgery likely would keep him out for at least a significant portion of the 2015 season as well, due to the 12- to 18-month recovery time.
Chatwood, in his third season with the Rockies, posted a 4.50 ERA over four starts this year. In four MLB seasons, he's gone 20-22 with a 4.34 ERA in 70 games, including 61 starts.
Andrew Simon is a reporter for MLB.com. Follow him on Twitter @AndrewSimonMLB.