Mariners-Cardinals Linked to Huge Trade That Would Shake Up AL West

Over the last decade, the American League West has primarily belonged to the Houston Astros. They've been able to dominate the division without much competition, leading to a handful of World Series titles.

But the Seattle Mariners came on very strong down the stretch last season and stole the division from the Astros. The Mariners surged into the postseason with World Series aspirations, but came up short.

This offseason, they've lost some talent from their roster, but they could still look to make big moves to improve before opening day. Right now, the AL West seems up in the air, but the Mariners could make a big move to swing it in their favor.

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Bleacher Report's Kerry Miller recently put together a huge mock trade that would bring St. Louis Cardinals stars Brendan Donovan and JoJo Romero to Seattle in exchange for top pitching prospect Kade Anderson.

Trading for Brendan Donovan would make the Mariners the AL West favorites

St. Louis Cardinals infielder Brendan Donova — Sep 13, 2025; Milwaukee, Wisconsin, USA; St. Louis Cardinals second baseman Brendan Donovan (33) hits a solo home run against the Milwaukee Brewers in the third inning at American Family Field. Mandatory Credit: Benny Sieu-Imagn Images | Benny Sieu-Imagn Images

"Last week, our Zach Rymer put together every team's wish list for what's left of the offseason. For the Mariners? It was an everyday infielder and bullpen depth," Miller wrote. "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."

The first thing to note is the fact that it's unlikely the Mariners would consider trading Anderson at this point. Anderson was one of the top picks in last year's MLB Draft and he looks like a future ace. Cutting ties with him would be a huge risk.

But if it means landing an All-Star infielder and a star lefty reliever, it would be very hard for the Mariners to say no.

This mock trade would make the Mariners the favorites in the AL West. They would be upgrading over Jorge Polanco at second base. They would also be upgrading their bullpen in a huge way.

Considering the rest of the division hasn't made any huge moves like this, the Mariners would be sitting pretty comfortably.

More MLB: Blockbuster 2-For-1 Mariners Trade Idea Brings All-Star SS to Seattle