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Astros Breakout Pitcher Brandon Walter Undergoes Tommy John Surgery

Originally posted on Houston Astros on SI | By Brad Wakai | Last updated Sep 23, 2025 6:27 PM ET

It's been a nightmare year for the Houston Astros when it comes to injuries.

Already knowing they were a little bit shorthanded from a talent perspective coming into the season after they let Alex Bregman walk in free agency and traded Kyle Tucker to the Chicago Cubs, the immediate struggles of Yordan Alvarez that was followed by his long-term injury was just a sign of things to come.

Both Hayden Wesneski and Ronel Blanco underwent season-ending elbow surgeries. Josh Hader picked up an injury that could have him on the shelf for the rest of the year even if they get into the playoffs. Isaac Paredes suffered a serious hamstring injury. Lance McCullers Jr. has been on and off the injured list. The outfield was a rotating cast depending on who was healthy. And now Alvarez is out again with an ankle injury.

Unfortunately, the hits keep coming for the Astros, as the team revealed that Brandon Walter has undergone Tommy John surgery to address the left elbow inflammation that has kept him on the IL since July 25.

Brandon Walter had Tommy John surgery yesterday, the Astros announced.
— Chandler Rome (@Chandler_Rome) September 23, 2025

This is another blow for Houston, who not only won't have the left-hander for the stretch run of the season and during the playoffs, but also likely won't have him for the entirety of next year based on the timing of his procedure.

Walter was signed by the Astros to a minor league deal on Aug. 25 of 2024. That came after he was released by the Boston Red Sox, the team that selected him in the 26th round of the 2019 draft. That pedigree doesn't suggest the lefty would amount to much, but he was a revelation for Houston when he was on the mound this season.

Brandon Walter Was Breakout Star for Astros

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The 29-year-old had an incredible start to the season with Triple-A Sugar Land, posting an eye-catching 1.94 ERA with 41 strikeouts across his first 10 appearances (six starts). That prompted Houston to call him up on May 20 when they needed another starting arm due to injuries, and he took his opportunity and ran with it.

Walter threw five scoreless innings against the Tampa Bay Rays where he gave up just three hits and struck out five batters with one walk allowed. While he was optioned back to Sugar Land the following day after that outing, he was recalled on June 8 and was a staple in the rotation until he got hurt.

The unheralded pitcher had a 3.35 ERA and 126 ERA+ across nine starts before hitting the injured list. He also had 52 strikeouts in 53 2/3 innings pitched, with an incredible number of just four walks issued to put his WHIP at 0.93.

It's unclear if Walter would have kept up that level of performance for the rest of the season, but there's no doubt that his absence for the rest of this year and potentially all of next will be felt by an Astros team that has needed starting pitchers.