The Mariners have “expressed willingness” to listen to offers on veteran right-hander Luis Castillo, according to a report from Alex Speier of the Boston Globe. The report comes on the heels of Mariners president of baseball operations Jerry Dipoto referring to dealing from the rotation as the club’s “Plan Z” for the offseason back in October. Indeed, it seems as though the club still isn’t necessarily enthused about the idea of parting with one of its starters, as Adam Jude of The Seattle Times reported this evening that while “anything is possible,” the club’s “public and private” stance entering the Winter Meetings is that they don’t want to trade from their rotation.
Even so, that the club is at least somewhat open to offers on Castillo is fairly notable. The right-hander, 32 next week, has three more guaranteed years on the extension he signed with the Mariners prior to the 2023 season. He’ll earn a $24.15MM salary each year from 2025 to 2027, and the contract also includes a possible option for the 2028 season. If Castillo misses more than 130 days due to a UCL procedure in 2025-2027, the contract includes a $5MM team option for the 2028 campaign. Otherwise, the contract includes a $25MM vesting option for 2028 that vests if Castillo throws at 180 innings during the 2027 season and receives confirmation from an independent physician after the season that he hasn’t suffered an injury that’d require him to begin the following year on the injured list.
In short, that somewhat complex deal guarantees Castillo $72.45MM over the next three seasons which could rise to $97.45MM over four years if his option vests. Notably, Castillo’s contract also included a full no-trade clause for the first three years of the deal that will remain in place through the end of the 2025 season, meaning the righty would have to approve of any trade he’s involved in. It’s unclear whether Castillo would be willing to entertain a trade out of Seattle or what his preferences might be, and it’s possible that the right-hander’s no-trade clause could render any trade talks moot if he’s unwilling to leave the Mariners.
Should Castillo and the Mariners both be open to a trade, however, it’s easy to see why he might be of interest to rival clubs. The righty’s $72.45MM guarantee over the next three years isn’t much more than what left-hander Yusei Kikuchi received from the Angels this winter, and Castillo compares quite well to the veteran lefty. Not only is he a year and a half younger than Kikuchi, but the right-hander has also roundly outperformed him on the field. Kikuchi’s pitched to a 3.96 ERA with a 3.78 FIP in 64 starts for the Astros and Blue Jays over the past two years, while Castillo has posted an excellent 3.43 ERA and 3.72 FIP in 74 starts since he first donned a Mariners uniform following the 2022 trade deadline. Given the ever-escalating prices on the starting pitching market and the hesitance many teams have shown engaging on pitchers encumbered by the Qualifying Offer, Castillo could be an attractive alternative to mid-market players like Sean Manaea and Nick Pivetta who remain available in free agency.
That’s not to say there are no causes for concern in Castillo’s profile, of course. Castillo has lost nearly two ticks of velocity off his fastball since his peak with the Reds, and since arriving in Seattle his once-superb groundball rate has fallen off to a more pedestrian 39.1% over the past two years. His strikeout rate dipped similarly this year, settling in at just 24.3% in 2024. That left him as a more-or-less league average starter by both results and peripherals this year, as he pitched to a 3.64 ERA with a 3.91 FIP and a 3.79 SIERA in 175 1/3 innings of work. That said, Castillo helps to make up for his diminishing results with volume. He’s been something of a workhorse throughout his career, pitching at least 150 innings in every wire-to-wire, 162-game season of his career while averaging nearly 178 innings per season since the start of the 2021 campaign.
Overall, Castillo is a solid, durable arm who can slot cleanly into the front or middle of virtually any club’s rotation. That should make him an attractive piece in a hot market for starting pitching, and if Castillo is open to a trade it wouldn’t be a shock to see the Mariners leverage their excellent rotation to help address other areas of the roster, even as they express reluctance to do so. After all, it’s worth noting that the club may face a budget crunch this winter that makes dealing Castillo and the $24.15MM he’s owed more palatable. While the Mariners are expected to enter 2025 with a payroll higher than their 2024 figure, that’s a point they’ve already reached: RosterResource projects Seattle for a $146MM payroll in 2025, and their year-end payroll this year was $144MM. Even with a small increase to payroll expected, that seemingly leaves very little room for the club to add salary.
That could pose a problem for the Mariners, given their reported interest in adding two infielders this winter. The club has a reported preference to add at the infield corners but has also been connected to middle infielders in the rumor mill, such as Cubs second baseman Nico Hoerner and KBO infielder Hyeseong Kim. Cubs first baseman Cody Bellinger and Phillies third baseman Alec Bohm are among the other players the Mariners have reportedly considered on the trade market, and the club also reportedly has interest in reuniting with either Justin Turner or Carlos Santana in free agency.
Of course, adding any of those players would cost money, and without a more substantial increase to the budget than expected it could be a tall order to add two of them. The Mariners would surely love to move on from the final year of either Mitch Haniger’s or Mitch Garver’s contract, but both sluggers have negative trade value coming off rough seasons. A Castillo trade, by contrast, likely could bring back a notable return while also clearing plenty of money off the club’s books to afford additional financial flexibility this winter to either dabble in free agency or take on salary on the trade market.
