The St. Louis Cardinals’ postseason hopes are dead in the water, unless they practically run the table and get some help, after being swept by the Seattle Mariners, dropping their record to less than mediocre at 72–75. With the postseason out of reach for the third straight year, the focus has shifted firmly to next year and beyond. At the trade deadline, the team moved on from key veterans Ryan Helsley, Steven Matz, and Phil Maton, leaving several questions about the pitching staff — none bigger than who will take over as the closer.
The Ryan Helsley Era is Over
For now, the Cardinals will have to find that answer internally. Sure, Ryan Helsley has shown overt interest in returning to the Cardinals, but with an ERA over 11 with the Mets, do the Cardinals want him back? He was great in with the birds on the bat on his chest, but not so much in the Big Apple.
One name getting plenty of attention is right-hander Riley O’Brien. Despite blowing a save on Wednesday in Seattle, O’Brien has flashed the stuff needed for the role, and St. Louis Post-Dispatch writer Derrick Goold recently made the case for him as the leading candidate heading into 2026.
Can Riley O’Brien be the Closer for the St. Louis Cardinals in 2026?
O’Brien has impressed in his first extended run with St. Louis, posting a 3-0 record, a 1.52 ERA, and three saves over 34 appearances. Armed with a fastball that can touch triple digits, he’s been one of the team’s most reliable arms since the deadline shakeup, showing the ability to miss bats in high-leverage situations.
Originally acquired from the Mariners after the 2023 season, O’Brien has steadily earned more responsibility in Oliver Marmol’s bullpen. Much like Helsley before him, he offers the kind of electric velocity and strikeout potential that makes him a natural fit for the ninth inning.

The Cardinals have added plenty of bullpen depth in recent years, giving them multiple options to explore. But unless the front office opts to spend big on a free-agent closer this winter, O’Brien may already be the frontrunner to inherit the job.
Whether St. Louis hands him the reins outright or lets him battle for the role in spring training, O’Brien’s emergence is one of the few bright spots in what has otherwise been another frustrating season at Busch Stadium.