The Seattle Mariners go for the series sweep tonight against the Houston Astros at Daikin Park and look to extend their divisional lead to three games.

Seattle has been one of the hottest teams in baseball, winning 13 of their last 14 games to surge to the top of the AL West. The run has been fueled by a mix of dominant pitching and explosive offense. The Mariners have scored 10 or more runs four times this month, while their pitching staff holds a strong 3.36 team ERA in September — the second best in the majors.

Seattle leads the MLB and home runs this month with 33, led by Cal Raleigh, who’s hit seven in September to bring his season total to 57 — the best in the majors and single-season team record.

On the mound tonight, Logan Gilbert gets the start for Seattle. He enters with a 5–6 record and a 3.53 ERA, but has been sharp this month, posting a 2.20 ERA across three September starts. He generally doesn’t go deep into games, making the Mariners’ bullpen a likely factor.

The Astros’ starter, Jason Alexander, is 4–1 with a 4.04 ERA. Acquired in May after being waived by the Athletics, he has turned into a valuable pickup for the Astros.

Since late July, Alexander has been excellent, going 2–2 with a 2.50 ERA over his last seven outings. His consistency has helped stabilize a Houston staff that has otherwise struggled for answers.

Prediction

The Mariners’ combination of power hitting and recent pitching form should carry them through, but Alexander has kept opponents off balance and could make this a close contest.

Prediction: Mariners 3, Astros 2

Starting Lineups

Seattle Mariners

1. Randy Arozarena — LF

2. Cal Raleigh — C

3. Julio Rodríguez — CF

4. Josh Naylor — 1B

5. Jorge Polanco — 2B

6. Eugenio Suárez — 3B

7. Dominic Canzone — DH

8. Victor Robles — RF

9. J.P. Crawford — SS

Starting Pitcher: Logan Gilbert (RHP) — 5‑6, 3.53 ERA 

Houston Astros

1. Jeremy Peña — SS

2. Carlos Correa — 3B

3. Isaac Paredes — DH

4. José Altuve — 2B

5. Christian Walker — 1B

6. Jesús Sánchez — RF

7. Yainer Díaz — C

8. Jake Meyers — CF

9. Mauricio Dubon — LF

Starting Pitcher: Jason Alexander (RHP) — 4‑1, 4.04 ERA 

How to Watch Mariners vs. Astros

First pitch for tonight’s game between the Astros and Mariners is set for 7:10 PM Eastern / 6:10 PM Central / 4:10 PM Pacific at Daikin Park in Houston.

The game airs live on ESPN and streams on the ESPN app and website.

If you’re a cord-cutter without an active livestreaming plan, you can watch the game for free by taking advantage of free trials from DIRECTV Stream, Hulu + Live TV, Fubo TV, or YouTube TV.

YouTube TV even offers a 20-minute free preview, without having to register for a trial — if you just want to catch part of the game.

Seattle Mariners vs. Houston Astros

Date: Sunday, September 21, 2025

First Pitch: 7:10 PM Eastern / 6:10 PM Central / 4:10 PM Pacific

Venue: Daikin Park, Houston, TX

TV: ESPN

Streaming: ESPN app and website