Houston Astros vs Seattle Mariners Prediction & Picks - MLB

USA - MLB

Houston Astros
9/21/25 19:10
Seattle Mariners

Prediction:

 

The Mariners -1.5 Runs

+119
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 by Lou Aguila | in MLB Picks

The Seattle Mariners will try to put the final nail in the coffin of the Seattle Mariners on Sunday as they go for a crucial series in Game 3 at Daikin Park.

The Mariners, 4-1 in their last five games against the Astros, are -143 road favorites against the Astros.

Current Form:

The Mariners (86-69) have extended their winning streak to three games as Cal Raleigh’s record-breaking 57th homer of the season ignited Seattle to a resounding 6-4 win over the Astros. Raleigh has surpassed Ken Griffey Jr. for the most home runs by a Mariner in a single season. Most of all, the Mariners’ victory on Sunday gave them a two-game lead over the Astros with 10 playing days left in the regular season.

The Astros (84-71) suffered their fourth loss in the last five meetings with the Mariners. After ending up scoreless in Game 1, Houston scored four runs in Game 2, courtesy of a Grand Slam in the seventh inning by Jeremy Pena. Unfortunately, it came after the Mariners had already established a 6-0 lead. The back-to-back losses put the Astros in danger of missing this year’s postseason as they are now tied with the Cleveland Guardians for the last wild card spot in the American League.

Pitchers Matchup:

Mariners RHP Logan Gilbert (5-6, 3.53 ERA) vs. Astros RHP Jason Alexander (4-1, 4.04 ERA).

Houston Astros vs Seattle Mariners Form

Table

Teams Pts P W L
8 Seattle Mariners
0.556 162 90 72
12 Houston Astros
0.537 162 87 75

Houston Astros and Seattle Mariners Latest Matches

Houston Astros
Houston Astros Latest matches
L W W W L L
Victories

3/6 (50%)

Defeats

3/6 (50%)

Sep 20, 2025 - MLB

Houston Astros
4 :  6
Seattle Mariners

Sep 19, 2025 - MLB

Houston Astros
0 :  4
Seattle Mariners

Sep 17, 2025 - MLB

Houston Astros
5 :  2
Texas Rangers

Sep 16, 2025 - MLB

Houston Astros
6 :  5
Texas Rangers

Sep 15, 2025 - MLB

Houston Astros
6 :  3
Texas Rangers

Sep 14, 2025 - MLB

Atlanta Braves
8 :  3
Houston Astros
L W W W L L
Victories

3/6 (50%)

Defeats

3/6 (50%)

Sep 20, 2025 - MLB

Houston Astros
4 :  6
Seattle Mariners

Sep 19, 2025 - MLB

Houston Astros
0 :  4
Seattle Mariners

Sep 17, 2025 - MLB

Houston Astros
5 :  2
Texas Rangers

Sep 16, 2025 - MLB

Houston Astros
6 :  5
Texas Rangers

Sep 15, 2025 - MLB

Houston Astros
6 :  3
Texas Rangers

Sep 4, 2025 - MLB

Houston Astros
4 :  8
New York Yankees
L W L W W L
Victories

3/6 (50%)

Defeats

3/6 (50%)

Sep 14, 2025 - MLB

Atlanta Braves
8 :  3
Houston Astros

Sep 13, 2025 - MLB

Atlanta Braves
2 :  6
Houston Astros

Sep 12, 2025 - MLB

Atlanta Braves
3 :  11
Houston Astros

Sep 11, 2025 - MLB

Toronto Blue Jays
6 :  0
Houston Astros

Sep 10, 2025 - MLB

Toronto Blue Jays
2 :  3
Houston Astros

Sep 9, 2025 - MLB

Toronto Blue Jays
4 :  3
Houston Astros
Seattle Mariners
Seattle Mariners Latest matches
W W L W W W
Victories

5/6 (83%)

Defeats

1/6 (17%)

Sep 20, 2025 - MLB

Houston Astros
4 :  6
Seattle Mariners

Sep 19, 2025 - MLB

Houston Astros
0 :  4
Seattle Mariners

Sep 18, 2025 - MLB

Kansas City Royals
0 :  2
Seattle Mariners

Sep 17, 2025 - MLB

Kansas City Royals
7 :  5
Seattle Mariners

Sep 16, 2025 - MLB

Kansas City Royals
5 :  12
Seattle Mariners

Sep 14, 2025 - MLB

Seattle Mariners
11 :  2
Los Angeles Angels
W W W W W W
Victories

6/6 (100%)

Defeats

0/6 (0%)

Sep 14, 2025 - MLB

Seattle Mariners
11 :  2
Los Angeles Angels

Sep 13, 2025 - MLB

Seattle Mariners
5 :  3
Los Angeles Angels

Sep 12, 2025 - MLB

Seattle Mariners
2 :  1
Los Angeles Angels

Sep 11, 2025 - MLB

Seattle Mariners
7 :  6
Los Angeles Angels

Sep 10, 2025 - MLB

Seattle Mariners
4 :  2
St. Louis Cardinals

Sep 9, 2025 - MLB

Seattle Mariners
5 :  3
St. Louis Cardinals
W W L W W W
Victories

5/6 (83%)

Defeats

1/6 (17%)

Sep 20, 2025 - MLB

Houston Astros
4 :  6
Seattle Mariners

Sep 19, 2025 - MLB

Houston Astros
0 :  4
Seattle Mariners

Sep 18, 2025 - MLB

Kansas City Royals
0 :  2
Seattle Mariners

Sep 17, 2025 - MLB

Kansas City Royals
7 :  5
Seattle Mariners

Sep 16, 2025 - MLB

Kansas City Royals
5 :  12
Seattle Mariners

Sep 7, 2025 - MLB

Atlanta Braves
2 :  18
Seattle Mariners

Houston Astros against Seattle Mariners : Head to Head (H2H)

Houston Astros

33 %

Seattle Mariners

67 %

Sep 20, 2025 - MLB

Houston Astros
4 :  6
Seattle Mariners

Sep 19, 2025 - MLB

Houston Astros
0 :  4
Seattle Mariners

Jul 20, 2025 - MLB

Seattle Mariners
3 :  11
Houston Astros

Jul 19, 2025 - MLB

Seattle Mariners
7 :  6
Houston Astros

Jul 18, 2025 - MLB

Seattle Mariners
6 :  1
Houston Astros

May 25, 2025 - MLB

Houston Astros
5 :  3
Seattle Mariners

Houston Astros - Seattle Mariners Key Points

  1. Houston is 7-13 SU in its last 20 games against an opponent in the American League West Division division.
  2. Houston is 0-5 SU in its last 5 games played on a Sunday.
  3. Seattle is 13-1 SU in its last 14 games.
  4. Seattle is 4-1 SU in its last 5 games against Houston.

Our Houston Astros vs Seattle Mariners Prediction

Averaging 5.8 runs per game on a .275 BA while sporting a 3.57 ERA over their last five games, the Mariners have been a little bit too good for the Astros after two games in this series. Houston, who has averaged 4.5 runs per game and pitched to a 3.60 ERA, surrendered only one homer in Game 2 after allowing four in Game 1. However, the Astros just could not stop the Mariners from outscoring them in every turn.

Mariners starter Logan Gilbert, who sports a 2.54 ERA over his last five starts, is poised to have another strong start vs. the Astros after surrendering one earned run over 5.2 innings in a 4-3 win by the Mariners last April 7. Desperately needing a win to keep their postseason bid alive, the Astros unleash Jason Alexander, who is 5-0 with a 2.93 ERA in his last five mound appearances. Honestly, Alexander might have a slight edge in this duel because of his five-game win streak. However, the Mariners have proven on multiple occasions that they can beat the Astros no matter who is on the mound. They have beaten Houston when Hunter Brown was the starter twice, and also have done it against Ryan Gusto and Framber Vásquez. Alexander has been spectacular recently, but the Mariners have the momentum after the back-to-back wins.

Fearless Forecast: Mariners 8, Astros 3

Our betting prediction for the Seattle Mariners vs. the Houston Astros: the Mariners -1.5 Runs

Prediction:

 

The Mariners -1.5 Runs

+119
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All tips are fully researched and given in good faith, but profits cannot be guaranteed.

Houston Astros vs Seattle Mariners Picks