Houston Astros Experiment With KBO Ace Has Officially Fallen Flat

The Astros signed Ryan Weiss coming off of a stellar year in the KBO and it hasn't gone according to plan.

Apr 6, 2026; Denver, Colorado, USA; Houston Astros relief pitcher Ryan Weiss (51) in the dugout during the fifth inning against the Colorado Rockies at Coors Field. | Ron Chenoy-Imagn Images

When Framber Valdez left in free agency, the Houston Astros knew they had to shore up the pitching staff behind their ace Hunter Brown. Aside from Brown, the rotation heading into 2025 seemed to be filled with pitchers who had been struggling with injuries, or league average back of the rotation arms.

They set out to fill their needs in the rotation during the offseason and brought in some high risk, high reward arms. They signed Japanese ace Tatsuya Imai to a three year deal, traded for Mike Burrows from Pittsburgh and brought in Ryan Weiss, a former Arizona Diamondbacks farmhand who was coming off a career year in the KBO.

Unfortunately for Houston, the pitching staff has dealt with injuries to Hunter Brown, Tatsuya Imai and Cristian Javier, while Burrows, their big trade acquistion, has allowed the most earned runs in baseball. This scenario would have been right where Weiss filled in, but the right-hander has been struggling mightily in Triple-A.

The Right-Hander Has Been Struggling in All Areas Since His Demotion

Houston Astros pitcher Ryan Weiss. | Troy Taormina-Imagn Images

Weiss got off to a nice start in Spring Training this season, throwing 10.1 innings and striking out seven with a 3.48 ERA. However, he walked eight batters and his struggle with command didn't get any better.

A fourth round pick in 2018, Weiss made his MLB debut in 2026 at 29-years-old. After a couple of shutout appearances in his second and third outings in relief, Weiss wasn't able to get any footing. He gave up six runs in relief on April 6 and from there wasn't the same.

He gave up at least two runs in each of his final five outings between April and May, giving up at least one homer in each appearances and walking multiple batters as well. In 26 innings in total, Weiss allowed 22 earned runs (7.62 ERA), gave up eight homers (2.8 HR/9) and allowed 20 walks (6.9 BB/9).

Weiss was subsequently demoted on May 5.

Things have not gotten better for the right-hander since arriving at Triple-A. In 20.1 innings, he has an 8.41 ERA and has 19 strikeouts to 10 walks.

In his latest start on Satuday, he allowed six earned runs in just 2.2 innings.

Weiss' struggles are a huge blow to Houston. They have dealt with injuries to key pitchers in Brown and Javier as well as both Burrows and Imai struggling, though Imai has seemed to find his footing in recent starts.

Sure, Spencer Arrighetti has been a godsend to a rotation that desperately needed reinforcements, but Weiss was supposed to be that guy who stepped up in his return to the states.

Unfortunately for the Astros, he wasn't able to translate his 2.87 ERA back in the U.S. It wasn't a huge contract, only one year, $2.6 million, but it's one that Houston was counting on with its rotation depth issues.

Weiss is still on the 40-man and maybe with some adjustments, or maybe a move to the bullpen, he and the Astros can still salvage some of his stellar 2025 season.