MANDATORY PHOTO CREDIT: Dilip Vishwanat/Getty Images

Riley O’Brien has had an unlikely journey to get where he’s at with the St. Louis Cardinals right now. And much like the Cardinals in general, O’Brien has exceeded expectations in 2026.

An eighth-round pick of the Rays in 2017, O’Brien actually originally was a starting pitcher. He was traded to the Cincinnati Reds in 2020, but he continued to struggle. O’Brien posted a 4.55 ERA in Triple-A and was designated for assignment early in 2022 and not long after was traded to Seattle.

St. Louis acquired O’Brien in a minor trade in November of 2023. O’Brien didn’t even have a 40-man roster spot with the Mariners at the time, and it was a low-risk move for the Cardinals to try and make something happen.

The Cardinals saw enough in O’Brien to send cash to Seattle to acquire him and place him on their 40-man roster.

Now a relief pitcher, O’Brien suffered a flexor strain early in 2024 and missed most of the season. He was only able to make eight big league appearances and 14 more in Triple-A during the 2024 season. He went into 2025 with only 10 1/3 career MLB innings pitched.

Last year, he threw 48 innings with a 2.06 ERA in the big leagues. Despite that, unfortunately, his 11.1% walk rate was quite high and his 22.6% strikeout rate was only average.

This year, however, it has been a breath of fresh air. Since taking over the closer’s role in St. Louis, he has notched a 2.70 ERA and 12 saves. His 29.5% strikeout rate, 2.6% walk rate and 62% ground ball rate are all also huge improvements from prior seasons.

The Cardinals entered Thursday at 24-18 and right on the thick of the National League Central. And their closer is a big reason why. The original expectations were low, but everything is going pretty well right now for St. Louis.