Astros vs Mariners Prediction 9/20/25 MLB Picks Today

The Seattle Mariners and Houston Astros meet Saturday in MLB action at Daikin Park. Here’s a Astros vs Mariners Prediction. This article will include a Astros vs Mariners Pick.

Seattle Mariners Betting Preview

The Seattle Mariners are 85-69 on the year and play the Rockies and Dodgers next. The Seattle Mariners are batting .244 on the season, have a .320 OBP, and a .420 slugging percentage. The Seattle Mariners pitching staff has a 3.89 ERA and a 1.23 WHIP. Julio Rodriguez leads the Seattle Mariners with 169 hits and 94 RBI, while J.P. Crawford and Cal Raleigh have combined for 286 hits and 172 RBI.

George Kirby gets the ball for the Seattle Mariners, and he is 9-7 with a 4.46 ERA and 120 strikeouts this season. Kirby is 3-1 with a 2.44 ERA and 41 strikeouts in his career against the Houston Astros.

Houston Astros Betting Preview

The Houston Astros are 84-70 on the year and play the Athletics and Angels next. The Houston Astros are batting .251 on the season, have a .317 OBP, and a .398 slugging percentage. The Houston Astros pitching staff has a 3.83 ERA and a 1.22 WHIP. Jose Altuve leads the Houston Astros with 148 hits and 74 RBI while Jeremy Pena and Yainer Diaz combined for 279 hits and 126 RBI.

Framber Valdez gets the ball for the Houston Astros, and he is 12-10 with a 3.59 ERA and 173 strikeouts this season. Valdez is 7-3 with a 3.22 ERA and 101 strikeouts in his career against the Seattle Mariners.

Seattle Mariners @ Houston Astros Betting Trends: September 20, 2025

• Probable Starting Pitcher: Framber Valdez      Record this season: 12-10      ERA: 3.59
• Home Record: 6-3
• Last 5 against Mariners: 2-1

Why the Houston Astros will win

• The favorites have won each of the Mariners’ last 12 games.
• The Mariners have lost six of their last seven road games against AL West opponents following a win.
• The Astros have covered the run line in each of their last eight games following a loss.
• The Mariners have failed to cover the run line in nine of their last 10 road games against AL West opponents following a win.
• The Astros have led after 3 innings in eight of their last nine night games.
• The Astros have led after 5 innings in eight of their last nine night games.
• The Mariners have lost the first inning in four of their last five games as road underdogs against American League opponents.

• Probable Starting Pitcher: George Kirby      Record this season: 9-7      ERA: 4.46
• Road Record: 4-4
• Last 5 against Astros: 1-1

Why the Seattle Mariners will win

• The Mariners have won seven of their last eight games as underdogs against the Astros.
• The Astros have lost four of their last five games as home favorites against the Mariners following a loss.
• The Mariners have covered the run line in each of their last 10 games as underdogs against the Astros following a road win.
• The Astros have failed to cover the run line in each of their last eight games as home favorites against the Mariners following a loss.
• The Mariners have led after 3 innings in five of their last six road games.
• The Mariners have led after 5 innings in each of their last four games against AL West opponents.
• The Mariners have won the first inning in each of their last three games against AL West opponents.

Total Runs Facts

• Seven of the Mariners’ last eight games as underdogs have gone OVER the total runs line.
• Each of the last four games between the Mariners and Astros at Daikin Park have gone UNDER the total runs line.
• The ‘Inning 1 OVER 0.5 runs’ market has hit in eight of the Mariners’ last nine games as road underdogs.
• The ‘Inning 1 UNDER 0.5 runs’ market has hit in seven of the Astros’ last eight games as home favorites against American League opponents.

Houston Astros Player Prop Facts

• Framber Valdez has recorded six or more strikeouts in each of his last five home appearances against AL opponents.
• Framber Valdez has recorded a win in three of his last four appearances against AL West opponents that held a winning record.
• Ramon Urias has recorded at least one hit in each of his last 10 appearances with his team as a favorite against AL West opponents.
• Ramon Urias has hit a home run in two of his last three home appearances against AL West opponents.
• Jeremy Pena ranks 6th amongst qualified players for Batting Average (.303) this season.

Seattle Mariners Player Prop Facts

• Julio Rodriguez has hit a home run in five of the Mariners’ last six road games against AL opponents that held a winning record.
• George Kirby has recorded six or more strikeouts in four of his last five appearances against AL West opponents.
• J.P. Crawford has recorded at least one hit in each of the Mariners’ last eight games as underdogs against AL opponents.
• George Kirby has recorded a win in six of his last seven road appearances against AL West opponents.
• Randy Arozarena has recorded a Double in each of the Mariners’ last four games as underdogs against the Astros.
• Cal Raleigh ranks 1st in the league in Home Runs (56) this season.

Matchup/League Facts

• The Astros rank 1st in the league for strikeouts this season (1438).
• The Astros rank 4th in the league for opponent batting average this season (.232).
• The Mariners rank 29th in the league for doubles this season (221).
• The Mariners rank 29th in the league for triples this season (9).

Astros vs Mariners Prediction

The Astros should have the edge at home with Valdez on the mound, but I’m leaning toward the Mariners, who have lost one game since September 6. The Astros have also lost 8 of the last 9 games Valdez has pitched. Kirby is having a rough September, and he’s been hit hard on the road, but the Mariners are one of the hotter teams in the bigs currently and making that playoff push. I’ll gladly side with the hot hand and the slightly more favorable price.