The Seattle Mariners collapsed late in the 2024 season and missed the playoffs again. Their offense cratered, posting the second-worst team batting average in all of baseball. After opening up a ten-game AL West lead in June and blowing it, they fired manager Scott Servais. Their offseason has been quiet so far but a big name looms on the trade market. The Mariners should trade for Cardinals third baseman Nolan Arenado before Spring Training.

The Cardinals are shopping their franchise third baseman as they enter a rebuild. They brought Chaim Bloom in to revamp their minor league operations and could use a few solid prospects to populate the pipeline. Arenado has three years left with over $60 million due to him before 2028. St Louis would have to retain money to make a trade with the Mariners work but it is one they should pursue.

The Mariners have seven names on MLB.com's 2025 Top 100 prospect rankings. While there are other teams with better high-end talent, the Cardinals could target Seattle's depth in a trade. Catcher Harry Ford would represent a short-term option and shortstop Felnin Celesten is a long-term play, as he is just 19 years old. Arenado is not the player he once was but asking St Louis to eat money would require a higher quality of prospects returning.

With Alex Bregman still available in free agency, teams are looking to add him to their infield next season. But if a team does not land him at third base, they could pivot to an Arenado trade before Spring Training opens. The Mariners can swoop in and make the deal before anyone is ready to get the best price and secure a star infielder.

The Mariners need Nolan Arenado for 2025

St. Louis Cardinals third baseman Nolan Arenado (28) hits a double against the San Francisco Giants during the fourth inning at Oracle Park.
D. Ross Cameron-Imagn Images
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On top of being in prime position to make the Nolan Arenado trade, the Mariners need his skills. They've lost three of their starting infielders from last year in free agency, including Josh Rojas who signed with the White Sox. Arenado is one of the best defensive first basemen of this generation and can fill a massive hole in the infield.

The Mariners also play in the hardest park to hit in across baseball, according to Baseball Savant. The offensive issues at T-Mobile Park are not new but this Seattle core has struggled with it. Arenado is not immune to the difficulty. His .125 career batting average in Seattle is his worst in any park. While this is something to consider when trading for someone, no one has good numbers in Seattle.

The AL West has changed a lot this offseason and it could benefit the Mariners in 2025. The Houston Astros traded Kyle Tucker and Ryan Pressly and may lose Bregman. And the Texas Rangers did not add much after a disappointing season. Meanwhile, the Mariners have one of the best pitching staffs in the league and could steal the division from the Lone Star State.

The question is not if the Cardinals will trade Nolan Arenado, it's when. It may not be this offseason especially if he does not waive his no-trade clause. But waiting until the trade deadline may benefit the Mariners, as they have other holes to fill. Getting guys like Jorge Polanco, who was great for them last year, to fill out the lineup could be their offseason plan. Then if the pitching has them near the playoffs in July, make the trade for Arenado.