Mariners' trade stance on Luis Castillo revealed

The Seattle Mariners were willing to listen to offers for Luis Castillo at this time last year, but the right-hander ultimately remained with Seattle. The club doesn’t intend to shop Castillo during this year’s winter meetings, reports Adam Jude of the Seattle Times.

The 32-year-old Castillo delivered steady results last season, pitching to a 3.54 ERA over 32 starts. He topped 175 innings for the third straight year. Castillo’s strikeout rate fell to a career-low 21.7%, but he countered the downturn with a career-best 6.2% walk rate. The veteran has now improved his walk rate in each of the past four seasons.

Castillo has two years and $48.3M remaining on the five-year, $108M deal he signed with Seattle back in 2023. The contract also includes a vesting option for 2028, which is triggered if Castillo reaches 180 innings in 2027. He’ll easily be the Mariners’ highest-paid player next season, though it’s a reasonable commitment for Castillo’s reliable innings.

Seattle acquired Castillo from Cincinnati at the 2022 trade deadline for a package of Noelvi Marte, Edwin Arroyo, Levi Stoudt, and Andrew Moore. Marte hasn’t completely lived up to his lofty prospect pedigree, but he provided meaningful contributions at the big-league level last season. Arroyo is among the club’s top infield prospects and could reach the majors as soon as 2026. Still, the deal has worked out well for the Mariners.

Castillo has been remarkably consistent with Seattle, recording an ERA between 3.34 and 3.64 in his three full campaigns with the team. His approach has changed significantly as a Mariner, with an increased focus on his fastball/slider instead of the changeup. Castillo boasted one of the more effective changeups in the league while in Cincinnati, and he used it as his primary pitch from 2019 to 2021. With Seattle, he’s pushed the offering behind his four-seamer, sinker, and slider in terms of usage. The changeup has easily been Castillo’s least-effective pitch by Run Value since he joined the Mariners. His fastball has emerged as a dominant pitch, notching a Run Value of at least 12 in four straight years.

Seattle’s standout starting rotation struggled with injuries last season. George Kirby and Logan Gilbert both missed extended stretches. Bryan Woo, who had largely been healthy for the first time, went down in September, but made it back for the ALCS. With Bryce Miller expected to avoid elbow surgery, the group should be back to full strength next year.

The Mariners have been on the offensive this offseason, re-signing Josh Naylor and swapping Harry Ford for Jose A. Ferrer. Even with Ferrer joining the squad, Seattle isn’t done making tweaks to the bullpen, per president of baseball operations Jerry Dipoto. “We will continue to add to our bullpen, in all different ways, like we always have,” Dipoto told reporters, including Jude. Dipoto mentioned that the team has been in touch with multiple veteran relievers and expects a deal to get done.

Led by Andres Munoz, the Mariners’ bullpen ranked eighth in SIERA last season. Ferrer will give the team a hard thrower from the left side, joining Matt Brash as a setup option ahead of Munoz. With Emerson Hancock preparing as a starter, Seattle could target a swingman on the open market. Another lefty alongside Ferrer and Gabe Speier could also make sense.