Reports out of Cardinals camp in Jupiter, Fla. on Tuesday morning indicated a possible snag in the progression of St. Louis closer Riley O’Brien’s readiness for mound action.
The 31-year-old right-hander who performed admirably in the ninth-inning following the Cardinals’ trade deadline shakeup to their bullpen last season is dealing with calf soreness, according to multiple reports.
Riley O'Brien is dealing with some "soreness" in his calf, #STLCards manager Oli Marmol said. Marmol expects to have some more clarity on the extent of O'Brien's calf issue.
— Daniel Guerrero (@TheDanGuerrero) February 17, 2026
O’Brien was set to participate in the upcoming World Baseball Classic as a member of Team Korea. Korea’s pool play runs March 5-10 in Tokyo as the team competes in Pool C in the upcoming tournament.
O’Brien logged six saves and a cumulative 2.06 ERA for the Cardinals in 2025 and entered the spring as a front-runner to resume closing pitching duties at the back-end of the St. Louis bullpen.