Seattle Mariners Add Intriguing Pitcher to 40-Man Roster in Monday Move

The Seattle Mariners filled out their 40-man roster with an interesting call-up on Monday.
Hudson Valley Renegades pitcher Blas Castano throws during a game against the Brooklyn Cyclones on July 27, 2022, at Dutchess Stadium.
Hudson Valley Renegades pitcher Blas Castano throws during a game against the Brooklyn Cyclones on July 27, 2022, at Dutchess Stadium. / Frank Becerra Jr. / The Journal News / USA TODAY NETWORK
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The Seattle Mariners 40-man roster is now completely full.

Monday marked the deadline for several different kinds of transactions for MLB teams. It was the deadline for players or teams to exercise options, for teams to extend qualifying offers to eligible players and for clubs to activate players off the 60-day injured list and put them on the 40-man roster.

The Mariners had two of the three transactions happen on Monday.

Seattle had no outgoing free agents eligible to receive a qualifying offer, meaning the only transactions that had to get done were activating three players (Sam Haggerty, Matt Brash, Jackson Kowar) off the injured list and waiting to find out if outfielder Mitch Haniger invoked his $17.5 million player option.

Aside from a confusing few hours where there was no confirmation over whether Haniger exercised his player option after the 2 p.m. PT deadline, there was hardly anything unexpected to come out of Monday for the Mariners.

Except for one thing.

Seattle selected the contract of 26-year old pitcher Blas Castano from the team's Triple-A affiliate on Monday. Castano's addition with Kowar, Haniger, Brash and Haggerty filled out the team's 40-man roster.

Francys Romero originally reported the roster move.

Castano played 29 games for the Rainiers and Double-A affiliate Arkansas Travelers in 2024 and started 26 games. He posted a 4.38 ERA with 108 strikeouts in 125.1 innings pitched.

Castano was originally signed by the New York Yankees as an international free agent out of the Dominican Republic on June 1, 2018. He was released by the organization on Aug. 8, 2023, and signed by the Mariners on Aug. 11, 2023.

Castano is an interesting choice for the 40-man roster, especially considering he's been used mostly as a starting pitcher since joining Seattle's organization. Given the Mariners' elite starting rotation, that might indicate the team wanting to get a look at Castano in spring training. It could also show that the team foresees Castano being used as reliever in the future.

It also could have been a way for the team to avoid Castano being available in the December Rule 5 draft.

Regardless of the reasoning, it likely won't be too long before Seattle fans get a good look at Castano.

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