Mariners Could See More Players in World Baseball Classic

Seattle has an MLB-high 16 players already on WBC rosters, and that number could grow to 17 or 18 with pitchers in the designated pool.

Published on Feb. 10, 2026

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The Seattle Mariners already have an MLB-high 16 players from their organization on rosters for the 2026 World Baseball Classic, and that number could rise to 17 or 18 with the addition of two pitchers in the designated pitcher pool. All-Star right-hander Luis Castillo is one of those pitchers in the pool for the Dominican Republic, while left-hander Jhonathan Díaz is in the pool for Venezuela. The Mariners also have Jonah Dipoto, son of team president Jerry Dipoto, in the designated pitcher pool for Italy.

Why it matters

The Mariners' high representation in the WBC highlights the depth and talent in their organization, with several key players getting the opportunity to compete on the international stage. Castillo's potential WBC debut would be notable, as he is the only member of Seattle's starting rotation who could participate.

The details

The designated pitcher pool allows WBC teams to have up to six pitchers who could potentially be called up to their roster if they advance past pool play. Castillo, a three-time All-Star, would be making his WBC debut if called upon by the Dominican Republic. The Mariners also have left-hander Jhonathan Díaz in the designated pitcher pool for Venezuela, and Jonah Dipoto, son of team president Jerry Dipoto, in the pool for Italy.

  • The World Baseball Classic is set to take place in March 2026.

The players

Luis Castillo

A three-time All-Star right-hander and the only member of the Mariners' starting rotation who could pitch in the 2026 WBC, as he is in the designated pitcher pool for the Dominican Republic.

Jhonathan Díaz

A left-hander who is in the designated pitcher pool for Venezuela.

Jonah Dipoto

The son of Mariners president of baseball operations Jerry Dipoto, he is in the designated pitcher pool for Italy.

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What’s next

If Castillo is called upon by the Dominican Republic, it would mark his WBC debut.

The takeaway

The Mariners' high representation in the World Baseball Classic, including the potential participation of All-Star pitcher Luis Castillo, showcases the depth and talent within their organization as they look to build on their success in the 2026 season.