Last Updated on July 18, 2025 10:51 am by Anthony Rome
The AL West-leading Houston Astros (56–40) kick off their three-game series against second-place Seattle. Despite a five-game cushion atop the division, Houston enters as an underdog for this opener. They are listed at +115 on the moneyline, while Seattle is favored at −135. This is a sign that park factors, home advantage, and momentum are tilting the script. What’s the smart bet in tonight’s Astros vs. Mariners matchup?
Game Matchup & Betting Odds
Houston Astros at Seattle Mariners
10:10 p.m. ET, Friday, July 18, 2025
T-Mobile Park, Seattle, WA
Astros vs. Mariners Betting Odds
According to oddsmakers from online sportsbook Bovada.lv, the Mariners are -127 moneyline favorites to beat the Astros. The Astros are +117 moneyline underdogs. The total, meanwhile, is sitting at 7.5 runs.
Astros vs. Mariners Public Betting: Bettors Love Seattle
As of this writing, our MLB Public Betting Page shows that 69% of the bets are on the Mariners moneyline. That said, this page is updated frequently. Make sure that you click on the link provided so that you’re getting the most updated information.
Mariners Momentum vs. Astros’ Edge
The Mariners are riding a second-half wave, fueled by star outfielder Julio Rodríguez and slugging backstop Cal Raleigh. They’re fresh off the Home Run Derby and expected to carry that off-season spark into tonight’s matchup . Seattle’s offense and home comfort give them an estimated 68 % chance to win. This is supported by consensus public betting leaning toward the home side.
Conversely, Houston brings postseason-tested grit and pitching depth to T-Mobile Park. They’ll look to lean on arms like Hunter Brown and Lance McCullers Jr.—both All-Stars this year. Though tonight’s starter hasn’t been officially announced yet.
Key Matchups & Player Highlights
Julio Rodríguez (SEA): Hitting with confidence post-All-Star break; featured in today’s main preview and heavily favored in moneyline analysis.
Cal Raleigh (SEA): Fresh from a Home Run Derby victory, he’s added pop and momentum to Seattle’s clean-up spot.
Hunter Brown (HOU): The reigning AL Pitcher of the Month enters the All-Star break with a 1.19 ERA and 39 strikeouts. He is potentially drawing tonight’s start. If not Brown, then another deep bullpen arm steps in.
Lance McCullers Jr. (HOU): Making his comeback bid after Tommy John, he’s provided stability and over 12 strikeouts in a start back in late May.
Jeremy Peña (HOU): A recent All-Star and hot in clutch spots (23 hits in 24 games before an IL stint). His bat may be crucial for Houston’s offense.
Astros vs. Mariners MLB BETTING PREDICTION
This series opener sets up as a clash between Seattle’s home swagger and Houston’s championship mettle. Expect the Mariners to come out swinging under the lights in their ballpark, with Julio Rodríguez and Raleigh providing the offensive punch.
Meanwhile, Houston’s pitching arsenal—anchored by Brown or McCullers—could keep things close if they bring heat and stamina. The Astros have had more recent success in this series, so I’m taking the value with Houston on the moneyline.
Astros vs. Mariners MLB Playoffs Prediction: HOUSTON ASTROS +117