Cardinals' Riley O'Brien Gets Mixed-Bag Injury Update

The St. Louis Cardinals' bullpen is going to certainly look a bit different on Opening Day than it did at this point last year.

St. Louis traded Ryan Helsley, Steven Matz and Phil Maton away ahead of the 2025 Major League Baseball trade deadline, The club made further changes throughout the offseason, including the addition of Justin Bruihl.

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While there has been turnover, there will still be familiar faces in town in 2026, including Riley O'Brien. He currently is dealing with an injury, though. O'Brien is dealing with a mild right calf strain. On the bright side, he said that it's trending in the right direction, as transcribed by MLB.com's Chuck King.

The Cardinals hurler is injured at the moment

Sep 20, 2025; St. Louis, Missouri, USA; St. Louis Cardinals relief pitcher Riley O'Brien (55) pitches against the Milwaukee Brewers during the eighth inning at Busch Stadium. Mandatory Credit: Jeff Curry-Imagn Images | Jeff Curry-Imagn Images

"One member of the quartet of St. Louis' potential closers has already sustained a setback," King wrote. Riley O'Brien incurred what he called a mild right calf strain while throwing a live bullpen session on Saturday. He hasn't thrown off a mound since. 'It felt better today than it did yesterday,” O'Brien said Tuesday. “Hopefully it's nothing too long-term.'"

On the negative side, King noted that the injury is putting his chances of pitching the World Baseball Classic "in doubt."

"Even if the injury isn't long-term, O'Brien's injury could have significant short-term implications. For starters, his availability to pitch for Korea in the upcoming World Baseball Classic is in doubt," King wrote.

O'Brien was one of the team's biggest breakout stars from the 2025 season. Before the campaign, he had made just 10 total big league appearances. In 2025, he made 42 and logged a 2.06 ERA in the process across 48 innings of work. He's someone to watch as the club attempts to determine a path forward at closer. Helsley was obviously traded away and the club used a variety of guys in the role afterward, including O'Brien and JoJo Romero.

It's a positive that he's trending in the right direction. It would've been nice to see him in action in the World Baseball Classic as well. He hasn't been fully ruled out for that as of writing, but this will be an injury to follow moving forward.

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