The Cardinals may have unearthed another potential shutdown closer

A common baseball refrain is that by Memorial Day, a team should know roughly how its season will shake out. But as the 2025 season reaches its halfway point, the St. Louis Cardinals are still searching for a clear direction, and it remains unknown as to whether the team will assume the role of buyer or seller at the trade deadline.

If the Cardinals decide that 2025 isn't their year and sell off their assets at the deadline, closing pitcher Ryan Helsley is likely to bring back the most value to the team. If he is dealt, the Cardinals will need to find another stopper to finish games. People have floated out suggestions as to who the replacement closer could be, but one pitcher who has gained helium in recent weeks could be a dark horse candidate for the job.

Riley O'Brien could supplant Helsley as the Cardinals' next closer.

Right-hander Riley O'Brien has pitched sensationally as of late and has emerged as a weapon at the back of the Cardinals' bullpen. St. Louis plucked O'Brien from the Seattle Mariners for cash considerations in November 2023, and he had been beset with injuries until recently, dealing with flexor tendon issues that caused him to miss four months of 2024 and part of spring training this season.

The Cardinals stuck with him through the maladies, and now, finally healthy, O'Brien has strutted his stuff. He has not allowed a run in any of his last eight appearances, and he has 10 strikeouts in 9.2 innings. His five walks allowed in that span are a bit higher than most would like to see, and if he can rein those in, O'Brien could sit among the nastiest relief pitchers in the game.

O'Brien's Stuff+, a stat that observes the physical characteristics of a pitch, is 114, with 100 as the average. That sits behind only Helsley as the best in the bullpen for the Cardinals. His Baseball Savant page indicates that his fastball velocity is elite, with an average of 97.8 mph, and his extension is excellent as well, at an average of 7 feet. This means that batters have less time to react to O'Brien's already zippy fastball because he releases it closer to the plate than most other pitchers do.

Because of the limited major league experience under O'Brien's belt, fans may not realize that he is already 30 years old, so he is unlikely to develop any further. But while he may not fit into the Cardinals' long-term future, O'Brien has shown lately that he has the arsenal to fill a hole in the bullpen and close out games in the major leagues. For an acquisition that was virtually free, that's a huge win for the Cardinals.