Astros vs Mariners Prediction and MLB Tips - 21 September 2025
Last updated: Sep 20, 2025, 11:11PM | Published: Sep 19, 2025, 7:32PM
The Houston Astros will take on the Seattle Mariners in Game of the League Series at Daikin Park on Sunday, beginning at 9:10am AEST.
The Astros will send Framber Valdez (12-10, 3.59 ERA) to the mound, up against George Kirby (9-7, 4.46 ERA) for the Mariners.
This article features Stats Insider's best betting tips for the Astros vs Mariners game, as well as the latest betting odds in Australia.
Who Will Win?
Using trusted computer power and data, Stats Insider has simulated the outcome of Sunday's Houston vs Seattle MLB match-up 10,000 times.
Our proven predictive analytics model gives the Astros a 54% chance of winning against the Mariners at Daikin Park.
Astros vs Mariners: Odds
The current betting odds in Australia for Sunday's MLB game at Daikin Park are listed here:
- Head to Head: Astros $1.87, Mariners $1.95
- Line: Astros -1.5 ($2.85), Mariners +1.5 ($1.44)
- Total (Over/Under 7.5 Runs): Over $1.91, Under $1.91
Odds are correct at the time of publication and subject to change.
Looking at the latest head-to-head odds, the bookmakers currently have the Astros at $1.87 and the Mariners at $1.95.
The Astros are 1.5-run favourites against the Mariners, with odds of $2.85 available at TAB.
For the underdog Mariners (+1.5) to cover the line, TAB offers odds of $1.44.
The over/under for total runs scored is set at 7.5 with TAB, which has odds of $1.91 for the over and $1.91 for the under.
According to Stats Insider's analytics model, the Mariners (+1.5) are predicted to cover the line 64% of the time, while the 7.5-run over/under is expected to go over 55% of the time.
Astros vs Mariners: Best Bets
- Head to Head: Houston at $1.87 with TAB
- Line: Astros -1.5 at $2.85 with TAB
- Total Runs: Over 7.5 at $1.91 with TAB
These Astros vs Mariners betting tips are based on world-class modelling and wagering experience to help you place better bets with your chosen online bookie.
Although the Mariners are more likely to cover the line, our best bet of Astros -1.5 is based on the chance of that happening, as suggested by our predictive analytics model, and the best odds available.
Astros vs Mariners: Prediction
Stats Insider provides full betting coverage of the Houston vs Seattle game on Sunday, including data-driven predictions and expert tips.
Remember, our model updates regularly, so refresh this article for the latest betting analysis before the Houston vs Seattle match-up.
As always, see Stats Insider's Best Bets for betting tips on every MLB game, plus predictions for a wide range of other sports.
Astros vs Mariners: Essential Details
The match-up between the Astros and Mariners at Daikin Park is scheduled to begin at 9:10am AEST on Sunday.
- Teams: Houston Astros vs Seattle Mariners
- Date: Sunday 21 September 2025
- Time: 9:10am AEST
- Venue: Daikin Park
All dates and times mentioned in this article are in Australian Eastern Standard Time (AEST), unless otherwise stated.
Conclusion
Our Houston vs Seattle predictions have been made based on 10,000 data-driven simulations of the game, all curated by our team of experienced data scientists and analysts. We use cutting-edge technology and machine learning to ensure our MLB tips are trustworthy and reliable, so that you can make informed decisions with confidence.
If you decide to use our predictions for betting purposes, it's important that you gamble responsibly and keep track of your money. For free and confidential support, call 1800 858 858 or visit gamblinghelponline.org.au.
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