Bryan Woo

Bryan Joseph Woo (born January 30, 2000) is an American professional baseball pitcher for the Seattle Mariners of Major League Baseball (MLB). He made his MLB debut in 2023. In 2025, he was named to the All-Star Game and All-MLB second team. In 2026, he was named one of the 50 greatest Mariners players. He pitched in college for the Cal Poly Mustangs.

Amateur career Growing up, Woo primarily played shortstop and third base. He had a strong arm but was not viewed as a prospect until growing eight inches during high school. He attended Alameda High School in Alameda, California, and did not pitch regularly until his junior year. As a senior in 2018, he went 8–2 with a 1.25 earned run average (ERA) while batting .422 as a switch hitter. He was named the player of the year in the West Alameda County Conference Foothill Division by the Mercury News. That summer, he played for the Peninsula Oilers in the Alaska Baseball League. The San Francisco Giants attempted to sign Woo at a scouting event in Alaska, but he chose to attend college. noting that it was the only program that recruited him as a pitcher and not as a two-way player. As a freshman in 2019, he had a 9.13 ERA over innings. He pitched only innings as a reliever for Cal Poly in 2020 before the season was cancelled due to the COVID-19 pandemic. In 2021, he had a 6.11 ERA over 28 innings before undergoing Tommy John surgery and missing the rest of the season. Woo started six of the 31 games he pitched in college, finishing with a 4–7 win–loss record, one save, a 6.49 ERA, and 89 strikeouts in innings.

Professional career The Seattle Mariners selected Woo in the sixth round with the 174th overall selection of the 2021 Major League Baseball draft. He signed with the Mariners for $318,200, which was $31,700 above the slot value of the draft pick. Still recovering from elbow surgery, he made his professional debut in June 2022 with the Arizona Complex League Mariners. In one game, he was rushed to the hospital after being hit in the face by a line drive but was not seriously injured. Over 16 starts for the three clubs, Woo posted a 1–4 record with a 4.11 ERA and 84 strikeouts in 57 innings. He played in the Arizona Fall League for the Peoria Javelinas after the season.

Woo started 2023 with the Double-A Arkansas Travelers. In nine starts, he had a 3–2 record and 2.05 ERA with 59 strikeouts in 44 innings pitched. Starting in place of Marco Gonzales, Woo had had a rough debut, allowing six runs in two innings. He won his first MLB game in his fourth start, besting the New York Yankees on June 22. He finished his rookie season with a 4–5 record, 4.21 ERA, and 92 strikeouts in innings. Manager Scott Servais said that Woo was still developing his breaking balls as a rookie. He made his first start on May 10. In his first six starts, he posted a 1.07 ERA, the lowest in Mariners history to begin a season. and made two more starts, earning losses in both outings, before returning to the injured list on June 25 with a hamstring injury. He was activated on July 12, resuming his turn in the Mariners rotation. He ended 2024 with a 9–3 record and 2.89 ERA, striking out 101 batters in innings over 21 starts, all improvements from his rookie season. He was the best MLB starting pitcher at avoiding base on balls, walking 2.6 percent of batters faced.

Woo was one of the most consistent pitchers in 2025. He was named to the All-Star Game in July. On July 10, he brought a no-hitter into the 8th inning against the Yankees. Before the All-Star break, he ranked third in the American League (AL) in strikeout-to-walk ratio and walk rate and accumulated more strikeouts than in either of his two previous seasons. Woo pitched at least 6 innings in his first 25 starts, a franchise record. During that stretch, he also allowed no more than two walks, the longest stretch to start a season since Cy Young in . That consistent length benefitted the Mariners' bullpen. Woo struck out a career-high 13 batters on September 13 in a win over the Los Angeles Angels. However, he was removed early from his next start due to a pectoral injury, earning a win over the Houston Astros but ending his regular season. He was 15–7 with a 2.98 ERA and 198 strikeouts in innings. He finished fifth in AL Cy Young Award voting and was named to the All-MLB second team. He ranked in the top five in the AL in wins, ERA, walks plus hits per innings pitched, strikeouts, strikeout-to-walk ratio, and double plays turned. His fastball was one of the most valuable pitches in the majors, according to Statcast, and he had the best command, according to PitchingBot analytics. However, he allowed 26 home runs, tied for eighth most in the AL. but he pitched in relief twice in the AL Championship Series. In the decisive Game 7, he allowed two runners on and was relieved by Eduard Bazardo, who promptly allowed a series-winning three-run home run, with two runs charged to Woo. Woo allowed 3 runs, 4 hits, and 3 walks while striking out 2 in innings in his first postseason.

Woo declined an invitation to pitch for the United States national team in the 2026 World Baseball Classic, citing his increased workload in 2025. He began the 2026 regular season third in Seattle's rotation, taking a no-decision while throwing a quality start in his first outing. After earning his first win of the season on April 19 and lowering his ERA to 2.25, Woo had consecutive poor outings, allowing a combined 13 runs in 9 innings in losses to the St. Louis Cardinals and Kansas City Royals. Throughout the 2026 season, he experienced a notable difference between home and road performance splits. Entering the trade deadline, he had a 2.20 ERA at home compared to a 6.71 ERA in away games.

Pitching style Woo primarily throws a four-seam fastball and sinker that both average . His offspeed pitches are a changeup and slider (some of which are labeled a sweeper). He throws his fastball and sinker close to 75 percent of the time, more frequently than most of his contemporary starters. He also throws a high percentage of strikes, which limits his base on balls.

Personal life Woo was born in Oakland, California to a White American mother and a Chinese American father. He grew up in the San Francisco Bay Area with his parents and sister. His parents attend all his MLB starts His paternal grandparents were born in China and moved to California. He visited China twice as a child. His maternal grandfather passed away in July 2025, the same day as Woo's final start before he pitched in the All-Star Game. In 2024, Woo became the last person born in Oakland to play an MLB game in Oakland. In 2026, he attended Super Bowl LX in nearby Santa Clara with several Mariners teammates.

During a 2024 start, Woo wore custom cleats with illustrations of professional wrestler Ric Flair, who was known for yelling "woo".