Cardinals' 4.13 ERA All-Star closer has turned into a big disappointment

The St. Louis Cardinals came into the 2026 season with very low expectations. But thanks to the breakouts of Jordan Walker and JJ Wetherholt, alongside others, they've become a legitimately competitive team.

While the postseason is a bit out of reach, they've had a very impressive season despite coming into the year as a rebuilding team. However, that doesn't mean all has gone well this season.

Closer Riley O'Brien, who made the NL All-Star team this season, is actually the Cardinals' biggest disappointment this season, according to ESPN's Bradford Doolittle. The reason why is simple: His second half has been very underwhelming.

Why Riley O'Brien has been Cardinals' biggest disappointment

"Only two teams have blown more saves than the Cardinals' relievers, and only one has allowed a higher percentage of inherited runners to score," Doolittle writes. "Typifying this issue has been closer Riley O'Brien, who leads the NL with 37 saves but has a 4.13 ERA and a bWAR that puts him right around replacement level."

O'Brien, the Cardinals closer who made the All-Star team this season, has become a bit of a liability out of the bullpen for the Cardinals.

Ironically, in a return trip to Philadelphia, O'Brien surrendered a 4-0 ninth-inning lead with two outs that ended in a walk-off home run by Kyle Schwarber for the Philadelphia Phillies.

That outing was just one of many in the second half of the MLB season that have led O'Brien to blow four saves and post a 5.40 ERA since the All-Star break.

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What makes this regression from O'Brien, from an All-Star closer to a replacement-level reliever, is that he has much greater potential than that.

"O'Brien has the stuff to be an elite closer, but he needs to make strides in consistency and command," Doolittle writes.

If O'Brien can get a bit more consistent and have better command of his pitches, he could be a very good reliever. But, as of right now, there is too much uncertainty with O'Brien to be trusted.

The Cardinals might've believed they found their closer of the future, but after his second-half production, that's become a big question mark for St. Louis and Oli Marmol as they head towards the end of the 2026 MLB season.

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