Seattle Mariners vs Houston Astros Prediction, Preview and Odds - 09/20/2025

Game Time: 7:10 pm ET, Saturday, September 20, 2025

Venue:  Daikin Park, Houston, TX

Where to Watch:  MLB.tv, ROOT Sports NW, SCHN

DraftKings:  Moneyline odds:  Mariners -108, Astros -112; Over/Under:  7.5 runs

Bet365:  Moneyline odds:  Mariners -105, Astros -115; Over/Under:  7.5 runs

BetMGM:  Moneyline odds:  Mariners -105, Astros -115; Over/Under:  7.5 runs

Seattle Mariners:  84-69 (1st place, AL West)

Houston Astros:  84-69 (2nd place, AL West)

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Seattle Mariners:  9-1 last 10

Houston Astros:  6-4 last 10

The Mariners are entering this series off a win and won their 3-game series against the Kansas City Royals 2-1 in their last series. They enter this game with an 84-69 record overall and have a road record of 36-42. This is the 2nd game of a 3-game series with the Astros on Saturday with the series opener still to be played on Friday. Their offense ranks 11th in the MLB with a .739 OPS. Bryan Woo is their starting pitcher on Friday while George Kirby is making his start in this game on Saturday. He is 9-7 with a 4.46 ERA this season. His team won their last 2 straight games this season with him making an appearance. In his last MLB regular season start, he allowed 2 ER, 2 HR, and 0 BB with 14 SO on 3 hits through 6.1 IP against the Los Angeles Angels.

The Astros are entering this series off a win and completed the sweep in their 3-game series against the Texas Rangers 3-0 in their last series. They enter this game with an 84-69 record overall and have a home record of 46-32. This is the 2nd game of a 3-game series with the Mariners on Saturday with the 1st game of this series still to be played on Friday. Their offense ranks 13th in the MLB with a .718 OPS. Hunter Brown is their starting pitcher on Friday while Framber Valdez is making his start in this game on Saturday. He is 12-10 with a 3.59 ERA this season. His team lost their last 3 straight games this season with him making an appearance. In his last MLB regular season start, he allowed 5 earned runs, 1 homer, and 4 walks with 2 strikeouts on 6 hits through 4 innings pitched against the Atlanta Braves.

The current betting odds have the Mariners listed as a slight underdog in this game according to Draftkings Sportsbook. The Astros have looked great in their games this season with their 84-69 record overall which has them right at the top of the AL West. They have also looked great in their own ballpark this year with their 46-32 home record. Meanwhile, the Mariners have looked really good in their games this season with their 84-69 record overall which has them right near the top of the AL West and in the division race. They haven't been a good road team though with their 36-42 road record this season. The Astros are 6-4 in their last 10 games and have been hot lately, but the Mariners have been even hotter with their 9-1 record in their last 10. The Mariners are going with Kirby in this one and he hasn't looked great this season. He is 9-7 with a 4.46 ERA, but lately he has looked a lot better and hasn't been giving up many runs. He is coming off a good start in which he gave up 2 earned runs and the team has had more success with him lately too, winning 2 games in a row now with him starting. The Astros are going with Valdez in this one and he has looked great this season. He is 12-10 with a 3.59 ERA, but lately he has been giving up a lot more runs and hasn't looked great. He is coming off a bad start in which he gave up 5 earned runs, something that has been a common theme for him over the last month, and the team has lost 3 games in a row now with him starting too. The Mariners are rolling right now, trying to win this division over the Astros, and this is a game they can take advantage of. The best way to place a bet here is on the Mariners to win this game. 

Mariners Astros Prediction:  Our MLB Pick for Saturday, September 20, 2025 (7:10 pm ET start time) is Mariners 4 Astros 2.

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Seattle Mariners: 257-220 (-7.9 units) on the moneyline in all games. 115-125 (-19.4 units) on the moneyline in road games. 53-71 (-7.6 units) on the moneyline as an underdog of +100 to +150. 21-13 OVER as a road underdog of +100 or higher.

Houston Astros: 115-104 (+6.8 units) on the moneyline when the money line is +125 to -125. 139-114 (+14.8 units) on the moneyline when playing against a team with a winning record. 184-148 (+15.2 units) on the moneyline vs. a team with a good bullpen whose WHIP is 1.350 or better. 23-14 OVER at home when the money line is +125 to -125. 

Seattle Mariners:  J. Kowar (RP) Fifteen Day IL - Shoulder. T. Thornton (RP) Sixty Day IL - Achilles. L. Evans (SP) Fifteen Day IL - Elbow. G. Santos (RP) Sixty Day IL - Knee. R. Bliss (2B) Sixty Day IL - Biceps.

Houston Astros:  Y. Alvarez (LF) Day To Day - Ankle. L. McCullers Jr. (SP) Fifteen Day IL - Hand. L. Garcia (SP) Sixty Day IL - Elbow. K. Ort (RP) Fifteen Day IL - Elbow. S. Arrighetti (SP) Fifteen Day IL - Elbow. J. Rooney (SP) Sixty Day IL - Concussion / Nasal. B. Sousa (RP) Fifteen Day IL - Elbow. B. Walter (RP) Sixty Day IL - Elbow. J. Hader (RP) Fifteen Day IL - Shoulder. I. Paredes (3B) Sixty Day IL - Hamstring. B. Rodgers (2B) Sixty Day IL - Oblique. Z. Dezenzo (RF) Sixty Day IL - Hand. P. Leon (RF) Sixty Day IL - Knee. R. Blanco (SP) Sixty Day IL - Elbow. H. Wesneski (RP) Sixty Day IL - Elbow.

“This is why we do what we do, and to be in this position and have exciting baseball this time of year. That’s why it’s there. Our guys are ready.” - Dan Wilson after his team’s win against the Royals in their game on Thursday.

“I think these guys know exactly what’s at stake. We played extremely well. Offensively, I thought the first inning was the key for our night. Having deGrom throw 30-plus pitches -- the first two guys get on and he strikes out Altuve and [Christian] Walker and you might see the end of that threat, but then Diaz [with] a big knock. I thought we carried that momentum, we made him work and we got some big hits.” - Joe Espada after his team’s win against the Rangers in their game on Wednesday.

Randy Arozarena (R) LF

Cal Raleigh (S) C

Julio Rodríguez (R) CF

Josh Naylor (L) 1B

Jorge Polanco (S) DH

Eugenio Suárez (R) 3B

Dominic Canzone (L) RF

Leo Rivas (S) 2B

J.P. Crawford (L) SS

Jeremy Peña (R) SS

Carlos Correa (R) 3B

Jose Altuve (R) 2B

Christian Walker (R) 1B

Victor Caratini (S) DH

Yainer Diaz (R) C

Jesús Sánchez (L) LF

Jake Meyers (R) CF

Zach Cole (L) RF

Batting Average:  Dominic Canzone (.300)

Hits:  Julio Rodríguez (168)

Home Runs:  Cal Raleigh (56)

RBI:  Cal Raleigh (118)

Stolen Bases:  Randy Arozarena (28)

Wins:  Bryan Woo (14)

Saves:  Andrés Muñoz (36)

ERA:  Jhonathan Díaz (0.00)

Batting Average:  Zach Cole (.333)

Hits:  Jose Altuve (148)

Home Runs:  Jose Altuve (26)

RBI:  Christian Walker (82)

Stolen Bases:  Jeremy Peña (20)

Wins:  Framber Valdez (12)

Saves:  Josh Hader (28)

ERA:  Jayden Murray (0.00)

Managers:

Seattle Mariners: Dan Wilson (2nd season)

Houston Astros: Joe Espada (2nd season)