Why Cardinals Must Trade Riley O'Brien After Series Loss to D-Backs

Riley O'Brien's stock could potentially rise.

Jun 28, 2026; St. Louis, Missouri, USA; St. Louis Cardinals pitcher Riley O'Brien (61) throws in relief against the Miami Marlins in the ninth inning at Busch Stadium. Mandatory Credit: Tim Vizer-Imagn Images | IMAGN IMAGES via Reuters Connect

The St. Louis Cardinals are reeling heading into a crucial series against the lowly Los Angeles Angels. They had a series win over the Arizona Diamondbacks in their grasp before letting a 7-0 lead slip away and being walked off in the 10th inning.

While many insiders are saying that the Cardinals are a clear buyer at the trade deadline, this could not be further from the truth. The team is lucky it still leads the race for the third National League wild card, but that may not last much longer.

As far as selling goes, the Cardinals have one clear candidate that they must trade, and that is closer Riley O'Brien.

Why Cardinals must trade Riley O'Brien

Jun 28, 2026; St. Louis, Missouri, USA; St. Louis Cardinals players (from left) Alec Burleson and Blaze Jordan congratulate St. Louis Cardinals pitcher Riley O'Brien after the St. Louis Cardinals defeated the Miami Marlins at Busch Stadium. Mandatory Credit: Tim Vizer-Imagn Images | IMAGN IMAGES via Reuters Connect

O'Brien is the trade chip that holds the most value at this point. He has three years of club control remaining after 2026 and finished the first half tied for the second most saves in the National League.

He is 3-3 with a 3.35 ERA this season and now has 25 saves. He was an even named an All-Star this summer. On the flipside, pitchers such as Dustin May and Ryne Stanek aren't going to have much value, especially after both struggled over the weekend.

Left-hander JoJo Romero may have some, but he is currently recovering from an appendicitis, so that might tank his value a little bit. This leaves Chaim Bloom with one clear trade chip, and that is O'Brien.

The Cardinals have made clear that they aren't going to chase short-term rentals at the deadline this summer, so the idea of them being soft buyers is a stretch. The Cardinals can probably get something similar to what they got for Ryan Helsley if they trade O'Brien, perhaps even a little better given his years of club control.

But holding onto him wouldn't be wise given that they are in the middle of a rebuild and must stay cognizant of the long-term plan. The Cardinals now have much more relief pitching depth in their system, so they could call somebody up to take his spot as the closer after he is gone.

The Cardinals may be in a playoff spot, but they can't lose focus when it comes to their plan. Sticking to it is the wisest course of action, and Sunday's meltdown should ultimately serve as proof that this this is what the Cardinals need to do as the deadline draws near.

They aren't going to get anything of value for May and Stanek at this point, and Romero has likely lost some trade value as well.