Kai-Wei Teng carded a 6.37 ERA in 2025. Norm Hall / Getty Images
To increase their roster flexibility and add more right-handed options in their bullpen, the Houston Astros are acquiring swingman Kai-Wei Teng from the San Francisco Giants in exchange for minor-league catcher Jancel Villarroel, multiple league sources told The Athletic on Thursday.
To clear a spot on the 40-man roster for Teng, Houston is designating J.P. France for assignment. Teng will be stretched out as a starter in spring training, but his most straightforward path to making the major league team may be as a long reliever. The Astros plan to open the season with a six-man rotation, magnifying the need for relievers who can pitch multiple innings.
The 27-year-old has minor-league options remaining. None of Bryan Abreu, Roddery Muñoz, Nate Pearson or Enyel De Los Santos do, but all four right-handed relievers have an inside track to make Houston’s Opening Day bullpen. Having Teng as insurance could help make the roster more adaptable.
Teng has struggled to a 7.30 ERA in 12 appearances over the past two seasons but continued to intrigue Giants officials because of his durability, his six-pitch mix and his ability to miss bats at all levels.
Used in a swingman role at Triple-A Sacramento last season, the right-hander posted a 3.95 ERA — respectable for the Pacific Coast League — and struck out a whopping 89 batters in 57 innings. But command and consistency have been issues. He’s issued 25 walks in 40 2/3 major league innings — and the Giants are out of balance with 24 pitchers on their 40-man roster.
San Francisco had to make a corresponding move when it announced its two-year contract with outfielder Harrison Bader, and Teng was a candidate to be designated for assignment.
Clearly, the Astros liked him enough to pay a modest price to jump the claiming line. Baseball America named Villarroel as the Astros’ No. 20 prospect in its most recent organizational rankings. The 21-year-old Venezuelan catcher reached High-A Asheville last season.
Teng is one of two current major leaguers from Taiwan and was heavily recruited to play in the World Baseball Classic, but has not yet committed to joining the team.