Seattle Mariners vs. Houston Astros Picks and Prediction for Sunday, September 21, 2025
The Seattle Mariners (85-69, 83-66-5 O/U) will be taking on the Houston Astros (84-70, 69-77-8 O/U) on Sunday evening in the final game of a three-game American League West series for our Mariners vs. Astros prediction. This is being written ahead of Saturday’s game. Right-hander Logan Gilbert (5-6, 3.53 ERA) is going to be pitching in this game for the Mariners while the Astros are sending righty Jason Alexander (4-1, 4.04 ERA) to the hill. From splits to bullpens, MLB predictions for Seattle Mariners vs. Houston Astros highlight the edge.
Mariners Looking to Capture AL West Title
The Seattle Mariners are looking to end the season strong as they are currently first in the AL West with an 85-69 record up to this point, as they try to avoid the AL Wild Card Round. The offense is performing well as they are 11th in MLB with a .244/.320/.420 team slash line while averaging 4.73 runs per game.
The Seattle Mariners were able to secure a 4-0 road win over the Houston Astros on Friday and it helps as Julio Rodriguez, Eugenio Suarez, Victor Robles, and Josh Naylor each hit solo home runs. Bryan Woo pitched well before leaving with an injury, as he won with five shutout innings.
Catcher Cal Raleigh (56 HR, .943 OPS) has been putting up one of the best seasons we have ever seen from a catcher offensively. Right-hander Jason Alexander (4-1, 4.04 ERA) will get the start here and is coming off a no-decision against the Texas Rangers, where he allowed three runs (one earned) on five hits with one walk and five strikeouts in 4.2 innings of work.
Injury Report for Seattle
- Pitcher Bryan Woo: Pectoral (Questionable)
- Pitcher Jackson Kowar: Shoulder (OUT)
- Pitcher Trent Thornton: Achilles (OUT)
- Pitcher Logan Evans: Elbow (OUT)
- Pitcher Gregory Santos: Knee (OUT)
- Second baseman Ryan Bliss: Biceps (OUT)
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Astros Looking to Hold Onto Tiebreaker
The Houston Astros are looking to play well as they are second in the AL West with an 84-70 record up to this point. The offense is playing at a respectable level as they are 15th in the sport with a .251/.317/.398 team slash line while scoring 4.23 runs per game.
The Houston Astros are coming off a 4-0 home loss on Friday to the Seattle Mariners and the team was 0-for-4 with runners in scoring position. Hunter Brown pitched well, but recorded the loss as he gave up two runs in six innings of work.
Second baseman Jose Altuve (26 HR, 78 runs) has been struggling compared to his AL MVP expectations and needs to step out of his recent funk. Righty Jason Alexander (4-1, 4.04 ERA) is going to be on the mound and is coming off a no-decision against the Texas Rangers, where he gave up three runs (one earned) on five hits with one walk and five strikeouts.
Injury Report for Houston
- Left fielder Yordan Alvarez: Ankle (OUT)
- Pitcher Kaleb Ort: Elbow (OUT)
- Pitcher Lance McCullers Jr: Hand (OUT)
- Pitcher Luis Garcia: Elbow (OUT)
- Pitcher Spencer Arrighetti: Elbow (OUT)
- Pitcher John Rooney: Concussion/Nasal (OUT)
- Pitcher Bennett Sousa: Elbow (OUT)
- Pitcher Brandon Walter: Elbow (OUT)
- Pitcher Josh Hader: Shoulder (OUT)
- Second baseman Brendan Rodgers: Oblique (OUT)
- Right fielder Zach Dezenzo: Hand (OUT)
- Right fielder Pedro Leon: Knee (OUT)
- Pitcher Ronel Blanco: Elbow (OUT)
- Pitcher Hayden Wesneski: Elbow (OUT)
Seattle Mariners vs. Houston Astros Pick
Spread Pick for Mariners vs. Astros
- Seattle Mariners ML (5 units)
If the Seattle Mariners win this game, they are in a great spot as they would hold the AL West tiebreaker over the Houston Astros and can continue to hold an advantage to try to get the bye in the American League. In the last 15 days, these offenses are on completely separate levels as Seattle is best in the sport with a .893 team OPS while averaging 6.85 runs per game, while Houston is 20th in MLB with a .671 team OPS while scoring 4.67 runs per game. All in all, go with the Seattle Mariners to secure the victory as the better bet.
Over/Under Pick for Mariners vs. Astros
- Under (4 units)
Both pitchers have been excelling during September thus far as Logan Gilbert is 1-0 with a 2.20 ERA and a .266 batting average against in 16.1 innings (three starts) while Jason Alexander is 0-0 with a 2.16 ERA and a 1.08 WHIP in 16.2 innings (three starts) heading into this game. These bullpens have also been showing the ability to step up over the course of the regular season as the Mariners are seventh with a 3.67 reliever ERA, while the Astros are 11th with a 3.75 bullpen ERA so far. The under 4-2-1 in their previous seven games against one another so take the under here.
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