Seattle Mariners at Houston Astros Predictions
This weekend, one of the most important series of the 2025 MLB season will take place in Houston. The Houston Astros are trying to maintain their American League West dynasty and will host the upstart Seattle Mariners, who are surging at the perfect time.
Seattle and Houston are in a back-and-forth race for the AL West lead, with the team that finishes second almost certain of gaining a wild-card playoff spot.
Houston has been battling age, roster turnover, and trying to milk out another season of success. However, few teams last more than a decade in success, and Houston has reached that milestone.
The Mariners have been transformed by All-Star catcher Cal Raleigh, who is in the hunt for the American League MVP Award.
On ESPN Sunday Night Baseball, the Astros will host the Mariners in the climactic final game of the series.
Mariners at Astros Preview
On Sunday, September 21, 2025, the Houston Astros will host the Seattle Mariners at Daikin Park in Houston, TX. Game time is 7:10 p.m. ET with television coverage on ESPN.
The probable starting pitcher for the Mariners is right-hander Logan Gilbert. So far in 2025, Gilbert is 5-6 with a 3.53 earned run average and 1.04 WHIP. He has 164 strikeouts in 120 innings pitched. In his last seven starts, his ERA is 3.93 with a 1.17 WHIP.
The Rangers' probable starter is right-hander Jason Alexander. Alexander is 4-1 with a 2.76 ERA and 1.11 WHIP. He was acquired from the Athletics in June.
Mariners at Astros Predictions
The Astros have been the more profitable team on the baseball betting board this season and have been a solid betting value at home.
Seattle has been one of the worst betting values on the road in MLB.
In Sunday night’s matchup, Houston makes the most sense as the proven value who will get a reasonable price against a quality opponent.
Mariners at Astros Prime Best Bet: Houston Astros
Mariners at Astros Betting Tips
Seattle is +71 moneyline units this season and -592 units on the road. Seattle is -1937 units on the run line.
Seattle is 83-69 and 84-62-6 over the total. The Mariners are 84-62-6 over the total. Seattle is a half-game behind the Astros for the American League West lead. The Mariners have gotten the cash in ten of their last 11 games. Seattle went over the total in eight of its most recent 11 games.
Seattle has MLB metrics of 10th for run production, 11th for OPS, 3rd for home runs, and 4th for stolen bases. By contrast, the Mariners rank 14th for earned run average, 10th for WHIP, 7th for fewest errors committed, and 10th for bullpen ERA.
All-Star catcher Cal Raleigh powers the Mariners with 104 runs, 22 doubles, 56 home runs, 118 RBIs, and a .247 batting average with a .948 OPS.
Houston is one of the most profitable teams on the board. The Astros are +936 on the moneyline and +653 units at home. Houston is -285 on the run line.
The Astros are 84-69 and 70-77-6 under the total. Houston got the money in five of its last six games. The Astros went over the total in four of their most recent six matchups.
Houston ranks 23rd in MLB for run production, 13th for OPS, and 17th for home runs. In turn, Houston ranks 8th for ERA, 5th for WHIP, 8th for fewest errors committed, and 11th for bullpen ERA.
Jose Altuve leads Houston with 78 runs, 22 doubles, 26 home runs, and 74 runs batted in. His batting average is .263 with a .768 OPS.
Mariners at Astros Head to Head and Key Stats
Overall, in the series between Houston and Seattle, the Astros have won nine of the most recent 17 meetings. Only six of the last 20 games between Seattle and Houston went over the total.
Specifically at Houston, the Astros got the cash in four of their most recent six games against the Mariners. Only six of the last 18 games between the Mariners and Astros at Houston went over the total.
