Mariners vs. Astros Prediction, Odds, Picks - September 21

The Seattle Mariners and Julio Rodriguez head into the final of a three-game series against Jeremy Pena and the Houston Astros on Sunday at Daikin Park. The Mariners are favored in this one, at -148, while the underdog Astros have +124 odds to play spoiler. Seattle (-1.5) is the favorite on the run line. The game's over/under is set at 8.5 runs.

Here's everything you need from a betting perspective on the Mariners-Astros game, regarding the run line, moneyline and total, plus expert picks.

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Mariners vs. Astros Highlights | MLB on FOX

Check out the best highlights between the Seattle Mariners and the Houston Astros.

Mariners vs. Astros Game Information & Odds

• When: Sunday, September 21, 2025 at 7:10 p.m. ET
• Where: Daikin Park in Houston, Texas
• How to watch on TV: ESPN

Mariners vs. Astros Prediction

• Score Prediction: Astros 5, Mariners 4
• Total Prediction: Under 8.5 runs
• Win Probabilities: Mariners 52%, Astros 48%

Mariners vs. Astros Betting Insights

• The Mariners have been favorites in 107 games this season and won 62 (57.9%) of those contests.
• Seattle is 31-17 this season when entering a game favored by -148 or more on the moneyline.
• The Mariners have a 59.7% chance to win this game based on the implied probability of the moneyline.
• The Astros have been chosen as underdogs in 55 games this year and have walked away with the win 32 times (58.2%) in those games.
• This year, Houston has won nine of 15 games when listed as at least +124 or worse on the moneyline.
• The Astros have an implied victory probability of 44.6% according to the moneyline set for this matchup.

Mariners Recent Betting Performance

• The Mariners won each of the seven games they played while the moneyline favorite in their last 10 matchups.
• Over their last 10 outings (all 10 of them had set totals), the Mariners and their opponents combined to hit the over six times.
• The Mariners are 7-3-0 against the spread over their past 10 games.

Mariners Recent Stats

Mariners Player Insights

• Cal Raleigh leads the Mariners in home runs (57) and runs batted in (119).
• Including all MLB hitters, Raleigh ranks 99th in batting average, 18th in on-base percentage, and third in slugging.
• Julio Rodriguez is hitting .269 with 31 doubles, four triples, 31 home runs and 39 walks.
• Rodriguez is 15th in home runs and 19th in RBI among all MLB hitters this year.
• Rodriguez carries a two-game streak with at least one hit into this contest. In his last five games he is hitting .250 with a double, a home run, two walks and three RBIs.
• Josh Naylor has put up a team-high batting average of .289.
• Naylor has at least one base hit in seven straight games. In his last 10 outings he is batting .366 with a double, two home runs, three walks and nine RBIs.
• Eugenio Suarez has 28 doubles, 47 home runs and 45 walks while batting .230.
• Suarez takes a two-game streak with at least one hit into this one. In his last five games he is batting .350 with three doubles, two home runs, a walk and four RBIs.

Mariners Team Props

Astros Recent Betting Performance

• The Astros have played as underdogs in five of their past 10 games and have gone 4-1 in those contests.
• The Astros and their opponents have combined to hit the over five times in their last 10 games with a total.
• The Astros have a record of 6-4-0 ATS over their last 10 games.

Astros Recent Stats

Astros Player Insights

• Jose Altuve has hit a team-high 26 home runs.
• In all of the majors, Altuve is 39th in homers and 64th in RBI.
• Jeremy Pena has a club-leading .304 batting average.
• Pena is 108th among all hitters in MLB in home runs, and 104th in RBI.
• Yainer Diaz is hitting .258 with 23 doubles, a triple, 19 home runs and 20 walks.
• Carlos Correa is batting .276 with 27 doubles, 13 home runs and 41 walks.

Astros Team Props

Mariners vs. Astros Highlights | MLB on FOX

Check out the best highlights between the Seattle Mariners and the Houston Astros.

FOX Sports created this story using technology provided by Data Skrive and data from Sportradar.

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