Luis Castillo Trade Proves Mariners Are Eyeing More Than Just Their Playoff Drought

Seattle made a big move to acquire Reds starting pitcher Luis Castillo. Is it enough to take the team beyond just the end of its 20-season playoff drought?

If the Mariners’ front office does not speak about the team’s playoff drought in explicit terms very often, well, it’s only fair—the streak predates any of them. (When Seattle last made the postseason in 2001, current president of baseball operations Jerry Dipoto was 33, only just done with his playing career.) Seattle’s drought has not been about the failures or poor planning or bad luck of any one regime. It’s bigger. But it’s not hard to see how it colors the experience of everyone involved: There is no way to escape the weight of the longest playoff drought in North American major professional sports. It affects what fans want, how they feel about the future, what they think about the past. October is no longer a month. It’s a fantasy.

Such is the backdrop for the Mariners’ news on Friday night. They’d entered deadline season with a comfortable hold on a playoff berth, and just as everything began to heat up, they dove in to make a splash: They acquired Reds starter Luis Castillo, the best pitcher available on the market, in exchange for four prospects (including some of the top names in their system).

It’s a big move. But it could be exactly what they need.

Yes, it required giving up quite a bit: Seattle sent 20-year-old shortstop Noelvi Marte, widely regarded as its top prospect, to Cincinnati; along with shortstop Edwin Arroyo and right-handed pitcher Levi Stoudt, two more highly ranked names; plus righty Andrew Moore. That’s a serious haul. But if that was the asking price for a pitcher like Castillo—under team control through the end of next season—it seems worth paying.

In Castillo, the Mariners have gotten an instant upgrade to the top of their rotation. The 29-year-old made his second All-Star team this year while enjoying the best season of his career thus far: 160 ERA+ with key improvements in his walk rate (2.96 BB/9) and home-run suppression (0.74 HR/9). Much of his progress this year seems to be tied to specific changes he’s made to his pitch mix. While his changeup used to be his signature pitch, he’s been throwing it less often this year than he has in any season since 2018, and he’s instead begun relying more on his fastball. His whiff rate on the pitch has gone from 31% last year to 39% now. (For more information on the adjustments he’s made this season to his four-seamer, here’s an interesting read from Jake Mailhot at FanGraphs.) And he’s established himself as a workhorse: There are just 10 pitchers who have thrown more than Castillo’s 533 innings since 2019. (One of them is new Mariners teammate Robbie Ray.) All of that adds up to a dream pick-up for Seattle—a pitcher who’s skilled, durable and still has a year to go until free agency.

Castillo has 14 starts for Cincinnati this season, totaling 2.86 ERA over 85.0 innings pitched / Kareem Elgazzar via Imagn Content Services, LLC

The Mariners’ July hot streak made their playoff outlook comfortable but certainly not guaranteed. They entered Saturday in possession of the second wild-card berth—0.5 games ahead of the Rays, who hold the third and final slot, and 1.5 games ahead of the Guardians, the first team out of the picture. This roster already had a very good chance of making the playoffs. (Per FanGraphs, their odds before the trade on Friday were 77%.) Now, it’s even better. But it’s especially notable in that the rotation was not an area of acute need here: It was a need, certainly, in the way starting pitching depth is a need for every playoff club, but it wasn’t especially pressing. The Mariners’ 3.68 rotation ERA is the sixth-best in baseball and fourth in the American League.

Watch the Mariners with fuboTV: Start a free trial today.

But that makes this move all the more exciting. This wasn’t patching up an obvious roster hole just to push them over the finish line. It was a transaction made by a contender that knows it’s a contender—one hoping to make a deep run and doing everything it can to bolster that possibility. The Mariners likely could have gotten away with simply adding some depth in the form of a back-end starter. Instead, they got the best pitcher available. That makes a statement. And it’s an exciting one for Seattle.

It’s especially important given the nature of the pitching market this year. There aren’t many front-end starters available: After Castillo, there’s A’s starter Frankie Montas, and then comes quite a gap until you hit Noah Syndergaard of the Angels and Castillo’s former Reds teammate Tyler Mahle. Just about every team could stand to add to their rotation. But the Mariners picking up Castillo makes it much harder for their competitors to do so this year. (Like, say, the Blue Jays—who are also in need of a starter and currently holding on to the first wild-card berth.) And, remember, the waiver trade deadline is gone: This is it.

There’s still more for the Mariners to do. A second baseman would be much appreciated; while Adam Frazier’s performance has improved a bit in recent weeks, they could benefit greatly from another option there, even if not as a regular starter. A little bullpen depth would be nice. But even if there isn’t much else to come—Seattle has already made the biggest move it could have (outside of, well, you know). The Mariners had to give up quite a bit of prospect talent to do it, but they’ve secured a top-tier starter who can anchor their rotation through next season, and they’ve shifted the market for everyone else. Their postseason drought was in good position to end this year anyway. But they’ve made it clear they won’t be taking any chances.

Sign up for the Five-Tool Newsletter to get all our MLB coverage in your inbox every Friday during the 2022 season.