Pitching Matchups For Series Between Seattle Mariners, Houston Astros
In this story:
Update (2:24 p.m. PT, July 18): The article has been edited due to a change in the Houston Astros probable pitchers.
SEATTLE — The Seattle Mariners are set to begin the second half of the season against their biggest American League West rivals, the Houston Astros.
The Mariners trail the Astros by five games in the American League West but hold the final AL Wild Card game by 1.5 games over the Tampa Bay Rays. Seattle will have a chance to make up ground on Houston in the division while creating separation from the rest of the field in the A. The M's will have a lot of momentum on their side after a series sweep against the Detroit Tigers right before the All-Star Break.
Here's an overview of the pitching matchups for the series between the Mariners and Astros:
Friday, July 18 — Luis Castillo (Seattle) vs. Brandon Walter (Houston)
Luis Castillo will be Seattle's opening starter for the second half, which makes sense given the midseason form he's shown lately. Castillo has five quality starts in his last eight outings. He struck out six, walked two, hit another and allowed three earned runs on six hits in five innings against the Tigers on July 11.
Luis Castillo, Vicious 95mph Two Seamer. 😤
— Rob Friedman (@PitchingNinja) June 14, 2025
Getting a buckle on a pitch on the outer third.
22 Inches of Horizontal Break. pic.twitter.com/7xn0AelrTs
Brandon Walter will make his eighth start of the season on Friday and will be coming off one of his better starts of the season. He fanned seven and allowed two earned runs on two solo home runs in six innings pitched against the Cleveland Guardians on July 9.
Saturday, July 19 — Logan Evans (Seattle) vs. Lance McCullers Jr. (Houston)
Logan Evans has been one of the most impressive rookies for the Mariners this season, but is coming off the roughest outing of his young career. He struck out two, intentionally walked one, walked two and allowed six earned runs on nine hits (two homers) in 4.2 innings against the New York Yankees on July 9.
Logan Evans, 2Ks in the 1st. pic.twitter.com/m04C2SEonk
— Rob Friedman (@PitchingNinja) May 28, 2025
Lance McCullers Jr. hasn't been able to regain his form since being activated off the injured list June 28, but could be due for a solid start after a longer break during All-Star week. McCullers has gone through the fourth inning just once in three outings since returning from the IL. He fanned five, walked two, hit one and allowed five earned runs on six hits (one home run) in three innings against the Texas Rangers on July 11. His ERA has ballooned from 4.91 before his time on the shelf to 6.48.
Sunday, July 20 — TBD (Seattle) vs. Hunter Brown (Houston)
Seattle's starter for the series finale is still listed as "to be determined." George Kirby, Logan Gilbert or Bryan Woo will start Game 3 between the two AL West foes, and the other two will pitch Games 1 and 2 against the Milwaukee Brewers when they come to T-Mobile Park. Woo pitched one inning in the All-Star Game on July 15 and will be rested for five days if he gets the nod.
Bryan Woo Mechanics (97 mph) pic.twitter.com/SBoOmYnrGG
— Rob Friedman (@PitchingNinja) July 16, 2025
Astros ace Hunter Brown will start the season finale in place of Framber Valdez, who was originally schedule to start Sunday's contest. Brown has been one of the best pitchers in the American League for the majority of the season, but struggled in his two most recent outings. He struck out 11 but walked six (one intentionally) and allowed 10 combined earned runs on 11 hits (three home runs) in 11 innings across two starts against the Guardians on July 8 and Rangers on July 13.
The series begins at 7:10 p.m. PT on Friday at T-Mobile Park.
Related Stories on Seattle Mariners
MARINERS COULD HAVE REASON TO BE WARY OF 2026 WORLD BASEBALL CLASSIC: In the latest episode of the Refuse to Lose podcast, ESPN insider Buster Olney talked about the potential of several Mariners players being absent from spring training for the international tournament. CLICK HERE
ANALYSIS: WHICH PLAYER NEEDS TO SHOW UP FOR SEATTLE MARINERS IN SECOND HALF?: The Mariners will need several players to step up or maintain their form if the team hopes to make the postseason. CLICK HERE
ANALYSIS: WHICH MARINERS HAS HAD MOST IMPRESSIVE FIRST HALF?: The Mariners had a lot of players exceed expectations this season, but none more than starting catcher. CLICK HERE
Follow Seattle Mariners on SI on social media
Continue to follow our Inside the Mariners coverage on social media by liking us on Facebook and by following Teren Kowatsch and Brady Farkas on "X" @Teren_Kowatsch and @RefuseToLosePod. You can subscribe to the "Refuse to Lose" podcast by clicking HERE.
