Diamondbacks manager Torey Lovullo made the announcement to reporters on Friday.

“Terrible news for him, terrible news for all of us,” Lovullo said. “The investment that he’s made, continuing to work and go and progress in the system, is just going to be put on hold for 14 months, give or take a month. It’s part of the game. It happens. Maybe there’s a sense of relief that he knows what’s going on. … He’s going to step out for a little while and come back stronger than ever.”

Walston, 23, went 1-0 with a 4.42 ERA in seven appearances for Arizona last season, including two starts. He also was 3-2 with a 4.85 ERA in 13 starts and one relief appearance with Triple-A Reno.

The Diamondbacks selected Walston with the 26th pick in the 2019 amateur draft.