JUPITER, Fla. (AP) — St. Louis Cardinals pitcher Alex Reyes needs season-ending Tommy John surgery on his right arm.

General manager John Mozeliak confirmed the diagnosis after an MRI. Reyes didn’t throw his scheduled bullpen session Tuesday because of a sore elbow.

The 22-year-old Reyes made his major league debut Aug. 9 and was 4-1 with a 1.57 ERA in five starts and seven relief appearances. His fastball averaged more than 97 mph.

Reyes, a candidate for the final spot in the starting rotation, had been feeling soreness in the days leading up to camp. He was also expecting to pitch for the Dominican Republic in the World Baseball Classic.