Blockbuster Cardinals-Mariners Trade Idea Brings Star Prospect to St. Louis

The Cardinals could land a potential superstar prospect in a blockbuster trade with the Mariners...

Sep 15, 2025; St. Louis, Missouri, USA; St. Louis Cardinals second baseman Brendan Donovan (21) take his position against the Cincinnati Reds in the sixth inning at Busch Stadium. Mandatory Credit: Joe Puetz-Imagn Images | Joe Puetz-Imagn Images

The St. Louis Cardinals have been one of the more active teams on the trade market for the last few months. They swung a trio of trades at the trade deadline last year, but they've been the most active team in trade talks this offseason.

Early in the offseason, the Cardinals opted to trade Sonny Gray to the Boston Red Sox for a haul of prospects. Soon after, Willson Contreras was traded to the Red Sox, too. Nolan Arenado was moved to the Arizona Diamondbacks during the offseason, too, but the Cardinals likely aren't done yet.

They could be looking to trade Brendan Donovan and JoJo Romero in the coming weeks. Both players are nearing the end of their respective contracts with the Cardinals, so a trade would make plenty of sense.

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There's even a chance the Cardinals look to trade both players together in one blockbuster deal.

Bleacher Report's Kerry Miller put together a huge trade package that would send Donovan and Romero to the Seattle Mariners in exchange for top pitching prospect Kade Anderson.

Kade Anderson would be a huge addition for the Cardinals

Jun 21, 2025; Omaha, Neb, USA; LSU Tigers starting pitcher Kade Anderson (32) pitches against the Coastal Carolina Chanticleers during the ninth inning at Charles Schwab Field. Mandatory Credit: Dylan Widger-Imagn Images | Dylan Widger-Imagn Images

"Last week, our Zach Rymer put together every team's wish list for what's left of the offseason," Miller wrote. "For the Mariners? It was an everyday infielder and bullpen depth. So a Donovan/Romero package sure would be sweet. Sweet enough to part with the No. 3 overall pick in the 2025 draft, though? Perhaps we'll find out."

Donovan has been closely linked to the Mariners for the last few months. He would be the ideal replacement for Jorge Polanco. Polanco took a deal with the New York Mets this offseason. Romero would fit perfectly in the backend of the bullpen in Seattle, too.

For the Cardinals, landing a superstar prospect like Kade Anderson would be a franchise-changing move. Anderson was the No. 3 pick in the 2025 MLB Draft, widely seen as the top pitcher in the draft class. The Cardinals selected Liam Doyle two picks later. If St. Louis could pair both prospects in their farm system, they would be stacked with top pitching talent for the next few years.

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