The Seattle Mariners will look for the road sweep over the Houston Astros at Minute Maid Park on Sunday, September 21, as the AL West rivals are battling for the top spot in the division.
My Mariners vs. Astros predictions and top MLB picks are calling for Seattle righty Logan Gilbert to lead the way to a convincing victory and extend the division lead for The Tridents.
Mariners vs Astros same-game parlay (SGP)
Mariners vs Astros prediction for Sunday Night Baseball
Mariners vs Astros best bet: Mariners -1.5 (+115)
Mariners vs Astros best bet analysis
The Seattle Mariners are rolling down the stretch with a league-high 5.94 runs per game in September, and they also have rolling righty Logan Gilbert toeing the rubber tonight.
Gilbert has spun a 2.54 ERA, 1.02 WHIP, and 3.08 xFIP across his past five starts while also posting an elite 12.39 K/9 and 28.4 K-BB%.
He’ll face a righty-heavy lineup, and the Houston Astros haven’t been nearly as imposing against right-handed arms with a 23rd-ranked wOBA and 26th-ranked ISO.
On the flip side, the Mariners have teed off on righties with respective ninth and seventh marks, and Houston starter Jason Alexander will be in tough to maintain his unsustainable .263 BABIP and 83.3% strand rate against a strong Seattle lineup.
Additionally, I value Seattle ranking second in wOBA and third in ISO on the road, with pitcher-friendly T-Mobile Park dragging down their overall numbers.
Mariners vs Astros same-game parlay analysis
Jorge Polanco has been scorching hot for the Mariners. He’s cashed the Over in this market in 13 of the past 17 games while totalling up an impressive nine runs, 23 hits, and 12 RBI with a monster 1.059 OPS.
Houston infielder Carlos Correa has also recorded a hit in 16 of the past 18 games, which includes a solid .300 batting average across nine contests at Minute Maid Park. He’s gone 5-for-16 with a .951 career OPS against Gilbert, too.
Mariners vs Astros odds
- Moneyline: Seattle -135 | Houston +115
- Run line: Seattle -1.5 (+126) | Houston +1.5 (-142)
- Over/Under: Over 8 | Under 8
Mariners vs Astros trend
The Mariners have covered the run line in 11 of their last 14 games (+9.70 units / 62% ROI). Find more MLB betting trends for Mariners vs. Astros.
How to watch Mariners vs Astros and game info
| Location | Daikin Park, Houston, TX |
| Date | Sunday, September 21, 2025 |
| First pitch | 7:10 p.m. ET |
| TV | ESPN |
| Mariners starting pitcher | Logan Gilbert (5-6, 3.53 ERA) |
| Astros starting pitcher | Jason Alexander (4-1, 4.04 ERA) |
Mariners vs Astros latest injuries
Mariners vs Astros weather
Odds are correct at the time of publishing and are subject to change.
Not intended for use in MA.
Affiliate Disclosure: Our team of experts has thoroughly researched and handpicked each product that appears on our website. We may receive compensation if you sign up through our links.
