St. louis: Riley O'Brien, the half-Korean pitcher for the St. Louis Cardinals, plans to pitch for South Korea at the World Baseball Classic (WBC) in March, a report out of St. Louis said.

According to Yonhap News Agency, Derrick Goold of the St. Louis Post-Dispatch reported that O'Brien, 30, accepted an invitation from the South Korean national team and is working on plans to travel to Japan, where South Korea will play all four opening-round games. The tournament is scheduled from March 5 to 17.

Thanks to lenient eligibility rules for the WBC, players can represent the country of birth of one of their parents, even if those players themselves weren't born in that country. For the 2023 WBC, South Korea had Gold Glove-winning infielder Tommy Edman, who was born in the U.S. to a Korean mother. O'Brien was born to a Korean mother and has the Korean name Chun-young.

South Korea's manager, Ryu Ji-hyun, expressed his hope earlier this month that three to four U.S. players of Korean descent would join his team for the WBC. Although Edman has been ruled out due to an offseason ankle surgery, South Korea might receive contributions from O'Brien and possibly Detroit Tigers outfielder Jahmai Jones. Seattle Mariners outfielder Rob Refsnyder, who was born in Korea but adopted by an American family as an infant, is another candidate.

O'Brien, originally an eighth-round pick by the Tampa Bay Rays in the 2017 draft, made his big league debut with the Cincinnati Reds in 2021 after a trade. The Reds traded him to the Mariners in April 2022, where he made one appearance. He joined the Cardinals in November 2023 and enjoyed his best major league season in 2025, compiling a 2.06 ERA over 42 games and 48 innings, with a 3-1 record and six saves. He struck out 45 and walked 22, with Baseball Savant data showing he relied heavily on his sinker and slider in 2025.

The final WBC roster is due February 3. South Korea has struggled in recent WBCs, failing to advance past the first round in the past three editions after strong performances in the inaugural tournament in 2006 and the 2009 final. Ryu initiated a preliminary training camp for around 30 players, predominantly from the Korea Baseball Organization, in Saipan on January 9, with plans to return to South Korea shortly. The final training camp will be held in Okinawa, Japan, starting February 15.

It remains uncertain if O'Brien and other MLB-based players will be able to join the Okinawa camp due to its overlap with their big league clubs' spring training or if they will travel to Japan in early March just before the tournament.