Houston Astros vs Seattle Mariners: Betting Line, Odds & Head-to-Head Breakdown

MLB · 2026 Season · Odds via DraftKings

As of now, this game hasn't started yet. It's scheduled for 9/22 - 9:40 PM EDT at T-Mobile Park. Check back once the game is underway for live score updates.

Heading into this MLB matchup, DraftKings lists the Seattle Mariners as the favorite at SEA -137, with the Houston Astros sitting as the underdog on the moneyline. The point spread currently sits at -1.5, and the over/under total for the game is set at 7, giving an early read on how competitive, and how high-scoring, oddsmakers expect this game to be.

These two teams already know each other well this season. SEA leads series 9-2, across 13 meetings so far. Head-to-head trends like this are often factored into betting lines and predictive models alike, since some matchups simply play out differently than a team's overall record would suggest.

Interestingly, the betting market and ESPN's statistical Matchup Predictor are in agreement here, both point to the Seattle Mariners as the side more likely to come out on top, with the model putting their win probability at 60%. When the numbers and the odds line up this closely, it's usually a sign the gap between these two teams is real, not just a betting-market quirk.

That betting line lines up with what the standings show. The Houston Astros currently carry a .494 win percentage on the season, compared to .468 for the Seattle Mariners. Whether that gap on paper translates to the scoreboard is a different question entirely, standings measure a whole season, while a single game can turn on one swing, one drive, or one bad quarter.

Betting lines, like win probabilities, are a snapshot, not a forecast set in stone, and they can shift right up until the 9/22 - 9:40 PM EDT start time as injury news, weather, and public money move the market. This page will keep reflecting the latest numbers as they update, so it's worth a final check before Houston Astros and Seattle Mariners actually take the field.

Odds are for informational purposes only and are subject to change. Please gamble responsibly.