Pyongyang: St. Louis Cardinals reliever Riley O'Brien was cut from the South Korean national team for the upcoming World Baseball Classic (WBC) on Thursday due to a calf injury, the latest blow to a team already short on pitching. The Korea Baseball Organization (KBO) announced Thursday it asked the tournament organizers to allow South Korea to replace O'Brien with Doosan Bears closer Kim Taek-yeon.
According to Yonhap News Agency, O'Brien, who has a Korean mother and an American father, was one of four U.S.-born players of Korean descent to make the South Korean roster for the March 5-17 WBC. The tournament allows players to represent the country of birth of one of their parents, even if those players themselves weren't born in that country. South Korea manager Ryu Ji-hyun had already named O'Brien as his closer and had planned to use the 31-year-old right-hander in high-leverage spots in late innings.
However, O'Brien suffered a mild right calf strain during a live bullpen session Saturday at the Cardinals' spring training site in Jupiter, Florida, and has not thrown off a mound since. South Korea will play Japan, Australia, Chinese Taipei, and Czechia in Pool C at Tokyo Dome.
O'Brien enjoyed his best big league season in 2025, when he posted a career-best 2.06 ERA in 42 games while recording six saves. In a message relayed by the KBO, O'Brien said his recovery from the calf issues had gone more slowly than he had hoped. "This selection meant a lot to me and my family. My family has already made travel plans to watch me play," O'Brien said. "I would love to be there myself, but I have to prioritize my health for the upcoming season. I wish the Korean national team all the best, and I hope to have another opportunity to represent the country."
Kim, 20, won the 2024 KBO Rookie of the Year award after notching 19 saves with a 2.08 ERA in 60 appearances. In 2025, the right-hander collected 24 saves and had a 3.53 ERA. He has 157 strikeouts in 131 1/3 career innings. Kim has been training with the Bears in Australia this month and is expected to join the national team camp in Okinawa, Japan, this week.
South Korea will also be without two key starting pitchers in Moon Dong-ju of the Hanwha Eagles (shoulder) and Won Tae-in of the Samsung Lions (elbow).