The Diamondbacks' starting pitching depth took a hit on Friday, as Blake Walston appears headed for Tommy John surgery. Manager Torey Lovullo told the news to reporters, including Alex Weiner of Arizona Sports.
Diamondbacks LHP Blake Walston is having Tommy John surgery, per Torey Lovullo.
— Alex Weiner (@alexjweiner) March 14, 2025
The immediate future for Walston is on hold, as he'll be out for the next 12-15 months, missing the entire 2025 season and the early part of 2026. He was pitching for a spot on the rotation depth chart or a possible long reliever spot in the bullpen, but he suffered the injury in his previous start against the Athletics in Las Vegas.
How is the Diamondbacks' pitching depth affected by Blake Walston's injury?
The Diamondbacks already face a dilemma with building their starting rotation. With the competition heating up between youngsters Brandon Pfaadt and Ryne Nelson for the final rotation spot, they're already seven pitchers deep into their rotation. However, seven starters are often not enough to get through a season. Both general manager Mike Hazen and top assistant Amiel Sawdaye have stated it will take eight to nine starters to get through the 162-game season.
The natural question to ask is who would be their eighth and ninth starter to begin the season. Going down to Triple-A, the answer is between Yilber Díaz, Cristian Mena, and Tommy Henry. Henry has the most experience of the three, with 32 career starts at the major league level compared to the four and one start that Díaz and Mena have. However, you can argue the two younger pitchers offer more future upside.
Further down the system includes top prospects trying to make an impact. Yu-Min Lin, Dylan Ray, and Spencer Giesting are all prospects who will be added to the 40-man roster by November. Lin is the closest to the major leagues, with a handful of starts in Triple-A in 2024.
If there is one team that can withstand such an injury, it's the Diamondbacks. Including Walston, they were very deep in starting pitching options beyond the major league roster thanks to many prospects getting a trial by fire last season.