The offseason focus for the Houston Astros has been quite clear. Pitching, pitching, and more pitching. That was the biggest need after failing to make the postseason for the first time since 2016. The Astros’ lacked bullpen depth, and injuries decimated the pitching staff.
Astros Increase Pitching Depth, Add Right-Handed Swingman in Trade
Houston is working to ensure that doesn’t happen again.
The Astros acquired right-hander Kai-Wei Teng in a trade with the San Francisco Giants on Thursday in exchange for minor league catcher Jancel Villarroel, according to Chandler Rome of The Athletic.
The Giants also received international bonus pool money in this deal. Villarroel was the Astros’ No. 13 overall prospect and is now the Giants’ No. 27 prospect. Right-handed pitcher J.P. France was surprisingly designated for assignment to make room for this move.
Sources: the Astros and Giants are nearing a trade that would send right-hander Kai-Wei Teng to Houston in exchange for catching prospect Jancel Villareal. Teng is an optionable swingman who can pitch out of the rotation or within a bullpen that could use more right-handed depth
— Chandler Rome (@Chandler_Rome) January 30, 2026
Houston has already added pitching earlier in the offseason with the trade for right-handed starter Mike Burrows and the massive international signing of Japanese starter Tatsuya Imai. They added another arm on Thursday night. The Astros have not historically targeted international pitchers, but the club has gone through that route now due to the overwhelming need for upgrades.
The Rundown on Kai-Wei Teng
The 27 year old has spent the past two seasons at the major league level with the Giants. The Taichung, Taiwan native owns a 7.30 career ERA in 12 games. He has pitched over 40 innings and carries a 1.70 WHIP.
This is clearly a pitcher that the Astros are looking to further develop with their coaching staff. They’ve been known to bring out the best in developmental pitchers, and Teng is another case. Houston saw some certain strengths in his game, and they’ll look to bring that out. However, the depth that he brings is much welcome.
Teng is a swingman, meaning he can be a long reliever in the bullpen or be another starter option for the Astros. More right-handed options were needed out of the pen, and Teng can provide that. He significantly increased his strikeout numbers, with 39 punchouts in 29.2 innings in 2025 with San Francisco.
More Analytics on the Right-Handed Swingman
Houston will look to keep those strikeout numbers high while reducing hits and runs allowed. The Astros are clearly high on Teng, as they moved on from France despite his proven success in the big leagues. Teng posted a 9.82 ERA in 2024, giving up 12 earned runs in 11 innings. There was a slight improvement last season with a 6.37 ERA in eight games, seven of them starts. Teng increased his MLB strikeout rate from 12.7% to 28.1% in 2025. A big reason for that was his increase in control.
Kai-Wei Teng boosted his big-league strikeout rate from 12.7% in 2024 to 28.1% in 2025. 📈
Matt Jordan breaks down the offseason focus that helped him more than double his MLB innings this year. 📝 pic.twitter.com/bd6yv37eCi— Tread Athletics (@TreadHQ) November 14, 2025
He certainly has a strong variety, with a five-pitch arsenal. Teng’s sweeper is his go-to pitch over 38% of the time, and it is quite effective. That pitch has an almost 35% whiff rate and draws just a .191 average against. His usage of the sweeper has dramatically increased from his third most used pitch in 2024 at just 17%. Teng used his sinker 44.1% of the time during 2024, and that has gone way down to 12.4%, the complete opposite of the sweeper.
The Potential
While Teng employs his changeup the least at just over 10%, it has been effective with a 30.8% whiff rate and .083 average against. There are two areas on Baseball Savant that show the potential the Astros were likely looking at. Teng’s 28.1% K rate was considered above average, as well as the .213 xBA.
Additionally, Teng’s 3.9% barrel rate and 31.6% hard-hit rate were considered great according to the site. The Astros see some potential, and they’ll likely look to use it in the bullpen. Justin Verlander, the former Giant was also available as a free agent, but it doesn’t look like the Astros are going down that path.
More Astros Pitching Depth
Houston also signed left-handed reliever Tom Cosgrove to a minor league contract and an invite to spring training, according to Jon Heyman of The New York Post. Cosgrove could emerge as a good lefty addition to the bullpen. The 29-year-old was impressive in his debut year with the San Diego Padres and posted a 1.75 ERA in 54 games. Cosgrove threw 51.1 innings and had a 0.97 WHIP along with 44 strikeouts, while allowing three home runs.
He really struggled in 2024 with an 11.66 ERA before being designated for assignment. Cosgrove was picked up by the Chicago Cubs and only made two appearances last season, but gave up one earned run in four innings. The Astros would love for him to find his 2023 form with the team.
(Top Image Credit: Jayne Kamin-Oncea-Imagn Images)