Astros vs. Mariners Prediction, Odds, Probable Pitchers and Prop Bets for Friday, July 18

Sean Treppedi | Jul 18, 2025

Cal Raleigh's magical season resumes in a low-scoring total against the Astros on Friday. / Rick Osentoski-Imagn Images

The Mariners ride back into the season with the headline of the season in Cal Raleigh, leading in home runs and RBIs. 

Houston’s offense, though missing Yordan Alvarez, remains steady behind Jose Altuve and Isaac Paredes, and still ranks first in batting average and top 15 in all key offensive metrics. 

The difference-maker on Friday could be on the mound, where Houston’s elite pitching staff leads the league in WHIP and ranks top five in ERA. 

Let’s break down a prediction for the matchup.

Astros vs. Mariners Odds, Run Line and Total

Odds via FanDuel Sportsbook

Run Line

• Astros +1.5 (-192)
• Mariners -1.5 (+158)

Moneyline

• Astros (+116)
• Mariners (-134)

Total

• Over 7.5 (-105)
• Under 7.5 (-115)

Astros vs. Mariners Probable Pitchers

• Astros: Brandon Walter (1-2, 3.98 ERA)
• Mariners: N/A

Astros vs. Mariners How to Watch

• Date: Friday, July 18, 2025
• Time: 10:10 p.m. ET
• Venue: T-Mobile Park
• How to Watch (TV): ROOTNW, Space City Home Network
• Astros Record: 56-40
• Mariners Record: 51-45

Astros vs. Mariners Prediction and Pick

This total feels a bit lofty for me, given a matchup between two of the better pitching teams in baseball, especially with the Astros' strong arms and the Mariners' home ballpark suppressing scoring. Houston ranks top five in WHIP, opponent batting average, and ERA, and they'll hand the ball to lefty Walter, who’s allowed just two walks in over 40 innings this season. 

Seattle is averaging only 3.9 runs per game at home and is hitting just .226 at T-Mobile Park, which is one of the toughest stadiums for offense. Luis Castillo has a 2.29 ERA at home and already blanked the Astros over five innings in April, a game that ended 2-1 in extra innings. 

Even though Raleigh and the Seattle offense exploded before the break, I’d say regression is likely against a rested Astros staff and bullpen that ranks third in ERA. The Astros, meanwhile, are missing their two biggest power bats in Kyle Tucker and Yordan Alvarez and are just 15th in runs scored despite leading the league in average. It’s also worth noting that Pena remains out of the lineup as well. With both teams leaning on their pitching and T-Mobile Park playing as a clear under venue, this game has all the makings of a 4-2 or 3-1 final.

Pick: Under 7.5 (-115 at FanDuel)

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Odds refresh periodically and are subject to change.

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