St. Louis Cardinals Acquire Minor League All-Star in Deal with Seattle Mariners

In an early offseason trade, the St. Louis Cardinals have acquired pitcher Riley O'Brien in a trade with the Seattle Mariners.

The Seattle Mariners have swung an early offseason trade with the St. Louis Cardinals.

Per Cardinals reporter Derrick Goold on social media:

#stlcards have acquired RHP Riley O'Brien in a trade with #Mariners. 

A PCL All-Star, the 28-year reliever had 86 strikeouts and a 2.29 ERA in 55 innings for Mariners' Class AAA team. He was set to become a minor-league free agent.

#stlcards have acquired RHP Riley O'Brien in a trade with #Mariners.

A PCL All-Star, the 28-year reliever had 86 strikeouts and a 2.29 ERA in 55 innings for Mariners' Class AAA team. He was set to become a minor-league free agent.

— Derrick Goold (@dgoold) November 6, 2023

There is no word yet on the return for the Mariners at this time, but it's likely to be cash considerations or a player to be named later.

O'Brien was not rated in the Top 30 Mariners prospects, per MLB.com. The Seattle-area native was drafted in the 2017 draft by the Tampa Bay Rays out of the University of Idaho.

He went 2-5 this past season with that 2.29 ERA. He struck out a whopping 86 batters in those 55.0 innings. It's understandable why the Cardinals would want him, considering they finished last in the National League Central in 2023.

As they look to remake the roster, they just need to take fliers on guys and see what sticks. As for the Mariners, maybe it's just as simple as getting something vs. losing him for nothing, but a player with that kind of performance and "stuff" is hard to let go of.

We'll better be able to judge the deal when the official return comes in. The Mariners finished 88-74 this past season and finished in third place in the deeply talented American League West.

They missed the playoffs on the second-to-last day of the season.

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