Cardinals relief prospect could be next call-up after latest roster move

The St. Louis Cardinals could be on the verge of a bullpen shake-up. Relief prospect Luis Gastelum has all but earned a promotion to MLB. And with the recent mishaps in the Redbird bullpen, there’s more than room for improvement. 

After an ineffective outing against the Padres, Chris Roycroft was designated for an assignment by the Cardinals, and the club decided to give the nod to Max Rajcic to make his MLB debut.

This season, the big right-hander has a 13.50 ERA in four innings pitched. It’s been a bumpy ride watching Roycroft pitch, and although the arm talent is real, he continues to falter against MLB talent. 

While Rajcic got the deserving nod this time, Luis Gastelum could be the next man up for the Cardinals' bullpen.

Gastelum, 24, is the Cardinals’ 21st-ranked prospect according to MLB Pipeline. His numbers this season have turned heads all over St. Louis. 

Kareem Haq, an analyst who covers the St. Louis Cardinals for @CardsProspects and @BirdsOnTheFarm on X, recently posted about Gastelum’s dominance: 

Gastelum’s allergy to runs has been his providence this season. The right-hander is known for his UFO changeup. 

MLB Pipeline wrote: “Gastelum’s success to this point stems from one pitch: his low-80s changeup. It’s a mesmerizing offering with a negative induced vertical break and plenty of armside run. It practically works like a left-handed breaking ball, but instead emerges from the 6-foot-2 right-hander’s low three-quarters delivery. Because of that action, the cambio was even more effective against righties than lefties last year, with a 64 percent whiff rate against same-side bats. (Not that lefties fared that much better.) Gastelum can throw a mid-90s fastball, but with ordinary movement, it only works to set up his beast of a change. He’ll occasionally work in a mid-80s sweeper too for something with big gloveside movement.” 

The reality of the situation is: it doesn’t matter how good or bad Gastelum is. It’s runway season, and Chaim Bloom’s playlist is on shuffle. 

The Cardinals need to give Luis Gastelum a shot in MLB

The biggest ailment of the Cardinal roster has been the bullpen. Misfortune in the latter innings cost St. Louis what could’ve been a potential sweep against the lowly Twins. Then, it added insult to injury in the Padres finale. 

St. Louis has been hesitant to succumb to recency bias. Although 2026 has been a daydream, Bloom still remembers John Mozeliak’s nightmares. Straying from the plan seems to entail adding come July, and if that’s the case, internal options are the fallback. 

The Cardinals lacked a lot of certainty in their bullpen entering the season, and since Riley O’Brien’s hot start has subsided, they’re back to square one. It’s a lot to ask for a closer, set-up man, and a great bulk innings arm, but one solid reliever is hiding in the wings, right under their nose. Gastelum is ready for his shot in the bigs. 

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