The Seattle Mariners are standing firm on their decision to keep Luis Castillo, a right-handed pitcher, on their roster. Despite some speculation last year, the team has no plans to trade him during this year's winter meetings, according to reports from Adam Jude of the Seattle Times.
Castillo, now 32 years old, has been a consistent performer for the Mariners. Last season, he maintained a solid 3.54 ERA across 32 starts, and impressively, he topped 175 innings for the third consecutive year. While his strikeout rate dipped to a career low of 21.7%, he compensated by achieving a career-best 6.2% walk rate, a statistic that has improved annually over the past four seasons.
Castillo is under contract with the Mariners for the next two years, with a total value of $48.3 million. This is part of a five-year, $108 million deal he signed with the team in 2023. The contract also includes a vesting option for 2028, which will activate if Castillo reaches 180 innings in 2027. Although he will be the highest-paid player on the team next season, his reliable performance justifies this commitment.
The Mariners acquired Castillo from the Cincinnati Reds at the 2022 trade deadline. In exchange, they gave up Noelvi Marte, Edwin Arroyo, Levi Stoudt, and Andrew Moore. While Marte hasn't quite lived up to his high prospect status, he still made valuable contributions at the major league level last season. Arroyo, meanwhile, is one of the club's top infield prospects and could make his major league debut as early as 2026. Overall, the trade has benefited the Mariners.
Castillo has been remarkably consistent since joining the Mariners, with an ERA between 3.34 and 3.64 across his three full seasons with the team. His pitching approach has evolved significantly, with a greater focus on his fastball and slider, moving away from his once-effective changeup. While in Cincinnati, Castillo's changeup was one of the best in the league, and he relied on it heavily from 2019 to 2021. With the Mariners, he has shifted his strategy, using his four-seamer, sinker, and slider more frequently. Since joining Seattle, Castillo's changeup has been his least effective pitch in terms of run value. Conversely, his fastball has become a dominant force, with a run value of at least 12 in each of the last four years.
The Mariners' starting rotation faced injury challenges last season. George Kirby and Logan Gilbert both missed significant time, and Bryan Woo, who had been healthy for most of the season, went down in September but returned for the ALCS. With Bryce Miller expected to avoid elbow surgery, the rotation should be at full strength next year.
The Mariners have been active this offseason, re-signing Josh Naylor and trading Harry Ford for Jose A. Ferrer. Despite these moves, the team isn't done making changes to their bullpen, according to president of baseball operations Jerry Dipoto. Dipoto has stated that the team will continue to add to their bullpen in various ways, and they are in contact with multiple veteran relievers, with a deal expected to be finalized soon.
Led by Andres Munoz, the Mariners' bullpen ranked eighth in SIERA last season. The addition of Ferrer provides the team with a hard-throwing left-handed option, joining Matt Brash as a setup man ahead of Munoz. With Emerson Hancock preparing as a starter, the Mariners could target a swingman in the free agent market. Another left-handed pitcher alongside Ferrer and Gabe Speier could also be a strategic move.
The Mariners' decision to keep Castillo and their active approach to the offseason suggest a team committed to building a strong roster for the upcoming season.
[Photo credit: Stephen Brashear, Imagn Images]
