Mariners to Promote Prospect Blas Castano

The 23-year-old outfielder will join the big league club ahead of a series against the Astros.

Mar. 11, 2026 at 5:10am

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The Seattle Mariners will promote top outfield prospect Blas Castano from their Triple-A affiliate in Tacoma, Washington, ahead of their upcoming series against the Houston Astros, according to reports from Francys Romero of BeisbolFR.com.

Why it matters

Castano is considered one of the Mariners' top young talents and his promotion to the major league roster is an exciting development for the team and its fans as they look to build on a promising 2025 season.

The details

The 23-year-old Castano has been tearing it up in the minors, batting .325 with 18 home runs and 54 RBIs in 92 games for Tacoma this season. His combination of power, speed, and defensive prowess have scouts and team officials high on his long-term potential.

  • Castano will join the Mariners' major league roster prior to their series opener against the Astros on Friday, March 14, 2026.

The players

Blas Castano

A 23-year-old outfield prospect in the Seattle Mariners' farm system who has been tearing it up at the Triple-A level.

Seattle Mariners

The Major League Baseball team based in Seattle, Washington that plays in the American League West division.

Houston Astros

The Major League Baseball team based in Houston, Texas that plays in the American League West division and has been one of the top teams in the league in recent years.

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What they’re saying

“Castano has really taken a big step forward this season and earned this opportunity to contribute at the big league level.”

— Jerry Dipoto, Mariners General Manager

What’s next

Castano will look to make an immediate impact as he makes his MLB debut against the division-rival Astros this weekend.

The takeaway

The Mariners' decision to promote one of their top prospects is an exciting sign that the team is committed to developing young talent and building a contender for the long-term.