Runs will be tough to come by tonight, as Seattle walks into Houston as +105 underdogs on Polymarket.
George Kirby and Peter Lambert go head-to-head, and we're leaning on their large sample size in this matchup as part of our Mariners vs. Astros predictions.
Let’s dive into my MLB picks for Friday, Aug. 14, and grow that bankroll before the weekend.
Who will win Mariners vs Astros today: Mariners (+105)
With 184 plate appearances under his belt, I'm tapping George Kirby to get the job done and cash us as a live underdog at Polymarket.
Over that span, the Houston Astros own just a .250 xBA and .286 xwOBA, while walking at just a 2.7% rate against the Seattle Mariners ace, giving us plenty to work with.
On the other side, Randy Arozarena (.251 xBA) and Julio Rodriguez (.358 xBA) are a combined 5-for-10 with a home run against Peter Lambert — let's ride this duo to the bank.
COVERS INTEL: One of the main reasons to feel warm and cozy about Mariners moneyline is Yordan Alvarez's numbers against Kirby. Over 22 at-bats, Alvarez is rocking a 29% K rate with just four hits to his name.
Mariners vs Astros Over/Under pick: Under 8.5 (-121)
Runs are going to be few and far between with this pitching matchup.
While Lambert doesn't have as large a sample size in this matchup as Kirby, he has still done a great job of suppressing runs here. Across 42 plate appearances, the right-hander is striking out this Mariners team at a 33% clip, limiting them to a .187 xBA.
Between these two pitchers, we should sail comfortably Under this number. I'd play this up to -130 at Polymarket.
Mariners vs Astros home run prediction: Julio Rodriguez (+474)
Rodriguez has the most success out of everyone on the Mariners against Lambert. The three-time All-Star is 3-for-5 with an xSLG of .942 in his small sample size.
It also helps that Daikin Park has given up the fifth-most homers in all of baseball. Rodriguez has found his power stroke, too, hitting a long ball in three of his last eight games.
- ML/RL bets: 3-6, -3.26 units
- Over/Under bets: 4-5, -1.80 units
Mariners vs Astros weather
Daikan Park features a retractable roof, so the weather will not affect game conditions tonight.
Mariners vs Astros odds
- Moneyline: Mariners (+105) | Astros (-113)
- Run line: Mariners +1.5 (-186) | Astros -1.5 (+178)
- Over/Under: Over 8.5 (+113) | Under 8.5 (-121)
Mariners vs Astros trend
The Under is 7-1-1 in the Mariners' last nine games against teams with a winning record. Find more MLB betting trends for Mariners vs. Astros.
How to watch Mariners vs Astros and game info
| Location | Daikin Park, Houston, TX |
| Date | Friday, Aug. 14, 2026 |
| First pitch | 8:10 p.m. ET |
| TV | Mariners.TV, Space City HN |
| Mariners starting pitcher | George Kirby (8-9, 3.68 ERA) |
| Astros starting pitcher | Peter Lambert (8-6, 3.09 ERA) |
Mariners vs Astros latest injuries
Odds are correct at the time of publishing and are subject to change.
Not intended for use in MA.
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