Jyun-Yue Tseng was born on November 7, 2001 in Taichung, Taiwan’s second-largest city behind Taipei. He attended the verbosely named Taichung Municipal Taichung Industrial High School and developed into a standout baseball player, at first as an infielder and later as a pitcher. On July 20, 2020, he was one of 123 amateur players to enter into the CPBL Draft, and the right-hander was one of 48 players who were selected by a professional club, with the Fubon Guardians picking him in the seventh round
of the process.
The 19-year-old Tseng made his professional debut in 2021 and quickly established himself as one of the preeminent relievers in the league, appearing in 57 games and posting a 1.80 ERA in 55.0 innings, allowing 36 hits, walking 16, and striking out 62 while saving 12 games. For his efforts, he was named the 2021 Rookie of the Year.
He followed up his Rookie of the Year campaign with statistically similar seasons over the next few years, cementing himself as one of Taiwan’s best relief pitchers. In 2022, he posted a 2.86 ERA in 50.1 innings over 47 games, allowing 35 hits, walking 18, and striking out 64 while saving 20 games. In 2023, he posted a 1.22 ERA in 51.2 innings over 54 appearances, allowing 29 hits, walking 17, and striking out 60 while saving 18 games.
After the 2023 season ended, Tseng was able to get the Guardians to post him, but he did not find much of a market outside of Taiwan and opted to remained with Fubon. In 2024, he posted a 1.52 ERA in 47.1 innings, allowing 36 hits, walking 14, and striking out 63 while saving 6 games. His streak of utter dominance ended in 2025, when he posted a 3.00 ERA in 36.0 innings over 34 games, allowing 30 hits, walking 13, and striking out 28.
Yue returned to the Taiwanese National Team in the 2026 World Baseball Classic, appearing in a pair of games and notching a single save, throwing 2.0 scoreless innings, not allowing a hit or a walk while striking out two. Returning to the Guardians for the regular season, the right-hander would go on to post a 1.57 ERA in 51.2 innings, allowing 48 hits, walking 13, and striking out 65 while saving 25 games.
After the season ended, the 24-year-old right-hander filed for international free agency and the posting request was approved by the Guardians.
The 5’8”, 150-pound right-hander would be one of the shortest pitchers in Major League Baseball. He throws from a high-three-quarters arm slot with a long arm action through the back, utilizing a hitch in his leg lift and wrapping his wrist during the full extension of his arm circle.
Tseng throws a fastball, cutter, slider, and splitter, with the latter being an exceptional pitch in Taiwan. The right-hander sits in the low-to-mid-90s with the pitch and tops out in the high-90s, flirting with triple digits. While the spin rate for the pitch is merely average for a four-seam fastball, hovering around 2300 RPM, the right-hander attacks batters from a flat approach angle thanks to his size and release point, heightening the pitch’s perceived induced vertical break that it otherwise does not produce through spin.
Tseng’s cutter, slider, and splitter are all pedestrian pitches, with all three sitting in the mid-to-high-80s. He is able to command all three, and the pitches tunnel well with one another and his fastball, but none have any standout pitch characteristics.
