ALCS Game 3 blowout sets up Luis Castillo for his defining Mariners moment

It's fair to say things didn't go quite to plan in ALCS Game 3 for the Mariners, as the Blue Jays jumped all over George Kirby and went on to secure a dominant 13-4 win on Wednesday evening in Seattle. As a result, even though the M's still hold a 2-1 lead in the series, a berth in their first ever World Series feels almost further away.

Enter Luis Castillo, who will get the start for the Mariners in a Game 4 in what figures to be the defining moment of his tenure in the Pacific Northwest. And in a lot of ways this seems almost apt, given what has thus far been an eventful 2025 for the three-time All-Star.

It began with speculation that the Mariners could conceivably trade Castillo, due to a combination of his age, declining productivity and the most expensive salary on the team's 2025 payroll. In the end, he wasn't moved due to holding a full no-trade clause on his contract for this year, and with him saying several times how much he loves playing in Seattle.

'The Rock' is just that in the Mariners' injury-hit rotation

This turned out to be a blessing in disguise for the Mariners — although to be fair, the organization was never fully invested in the idea of trading Castillo. They had to contend with varying degrees of injuries and absences to three main members of the rotation, but fortunately for them the 32-year-old righty lived up to his nickname of "The Rock" as he led the team with 32 starts.

Despite his reliability, a nightmare outing versus the New York Mets in mid-August — albeit in a 11-9 win for the M's — began a run which saw concern grow for Castillo. Over a stretch of four starts he produced a 10.06 ERA, 7.01 FIP and 2.18 WHIP in 17.0 innings, as he seemed to be turning into a liability for the team.

However, one thing you can never deny is the remarkable mental fortitude of Castillo as well as a healthy amount of stubbornness. As per Daniel Kramer of MLB.com, following a demoralizing 10-2 road loss to the Tampa Bay Rays, he effectively said he wasn't going to change anything about his approach and that the good times would return.

The return of the best version of Luis Castillo

Castillo proved to be a man of his word, as he proceeded to play some of the best baseball of his time with the Mariners during his final four starts of the regular season. Over 25.1 combined innings, he produced a 1.07 ERA, 2.50 FIP and 1.06 WHIP, to enter the playoffs in high spirits and with renewed confidence installed among the M's fanbase.

This tremendous form continued for Castillo in his first start of the postseason, in Game 2 of the AL Division Series versus the Detroit Tigers at home. While he only last 4.2 innings, his removal was more strategic than anything, as he allowed just one hit and no runs and played a vital role in the Mariners winning 3-2 and tying the best-of-five series at one game apiece.

The Dominican Republic native again played a vital role for the Mariners in the winner-takes-all Game 5 clash with the Tigers, in what turned into an instant classic over 15 tense and gruelling innings. He came in to record the final four outs of the M's eventual 3-2 win and he did it with the minimum of fuss, by not allowing a single hit or walk.

The question now is whether Castillo can continue the excellent start to his postseason in what figures to be a potentially dangerous matchup, as the Blue Jays are an aggressive lineup and he throws a ton of fastballs. As per Baseball Savant his average of 95.0 MPH on his four-seamer is the lowest of his nine years in the majors, although it should also be noted he ranks in the 90th percentile this season for Fastball Run Value.

Considering Luis Castillo's gameplan for dealing with the Blue Jays

What will be key to Castillo's approach is mixing up his pitches when he has to. While his four-seam fastball has accounted for 46.4 percent of his pitches, he has also thrown his sinker and slider 21.9 percent and 20.4 percent of the time respectively (along with 11.4 percent for his changeup).

Helping give Castillo confidence is that this game is taking place in Seattle, where he has been demonstrably better than on the road this year. This is highlighted by a 2.60 ERA at T-Mobile Park in 17 stats compared to a 4.71 ERA on his travels in 15 outings.

At the same time, it does also seem worth noting that Castillo was excellent the last time he faced the Blue Jays in the playoffs, throwing 7.1 innings of shutout ball in 4-0 win in Game One of the 2022 Wild Card round. While the opposing lineup is a lot different this time around, it did still include George Springer, Vladimir Guerrero Jr. and Alejandro Kirk.

One final aspect is that Max Scherzer will be taking the mound for the Blue Jays in Game 4. As much as it's been a rough season for the 41-year-old with a 5.19 ERA, 4.99 FIP and 1.294 WHIP over 17 starts, this is still the same pitcher who has three Cy Youngs and two World Series championships to his name.

Not that we would expect this to faze Castillo who, while he didn't outduel him per se, still got the better of Tarik Skubal in Game 2 of the ALDS. Ultimately, Mariners fans wait nervously to see what version of Castillo will turn up on Thursday evening after his up-and-down year, with the stage set for the biggest moment of his Major League career.