For most of the 2025 season, the Houston Astros have held a tenuous lead in the American League West.
Recently, the Seattle Mariners and Texas Rangers have been lurking close behind on the MLB board.
On Sunday Night, the Astros will host the Mariners in one of the biggest games of the 2025 season.
Houston has not been in top form at the most important time of the year. At the same time, Seattle has taken gamblers on a rollercoaster ride, but has recently caught fire.
Of course, Houston is the far bigger brand at the betting window. Most important of all, they are profitable.
On Sunday, betting interest at Bookmaker is expected to reach NFL levels for this showdown matchup. The Astros are a well-established power brand with a substantial public cache. But sharps like how the Mariners are operating under the radar.
Explore the latest MLB betting lines and predictions for Sunday Night Baseball.
MLB Betting Lines
Seattle Mariners at Houston Astros Betting at Bookmaker
Daikin Park in Houston, TX, is the venue for the Sunday, September 21, 2025, matchup of the host Houston Astros and visiting Seattle Mariners. First pitch for this American League West showdown is at 7:10 p.m. ET with television coverage on ESPN.
The Seattle Mariners have not been very profitable this season. Specifically, on the road, they have been in deep red ink. The Mariners have given gamblers a blood bath on the run line in 2025. Seattle is trending over the total this year.
The Houston Astros have been profitable in 2025. Houston has been a reliable betting value at home. By contrast, the Astros have been in the red with the run line. Houston is trending slightly under the total this year.
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Seattle Mariners
The Seattle Mariners are 82-68 and 82-62-6 over the total. The Mariners are fighting back and forth with the Houston Astros for the National League West lead. The team that is in second place will be in prime American League wild card position.
Late on, the Mariners are on fire with nine payouts in their last ten games. Seattle went over the total in six of their last nine tilts.
The Mariners have MLB metrics of 10th for run production, 12th for OPS, 3rd for home runs, and 4th for stolen bases. By contrast, Seattle ranks 14th for earned run average, 8th for WHIP, 7th for quality starts, 6th for fewest errors committed, and 7th for bullpen ERA.
The Seattle Mariners are +95 units on the moneyline and -1962 units on the run line. Seattle is -568 units on the road and is trending over the total.
Houston Astros
The Houston Astros are 82-69 and 69-76-6 under the total. Late on the Astros won four of their most recent six games. Houston has gone under the total in five of its most recent eight games.
Overall, Houston ranks 25th for run production, 13th for OPS, and 17th for home runs. The Astros rank 9th for earned run average, 5th for WHIP, 3rd for quality starts, and 8th for fewest errors committed. Houston ranks 10th for bullpen ERA.
The Astros are +702 units on the moneyline and -419 on the run line. The Astros are +418 units at home and trending under the total.
Jose Altuve leads Houston with 77 runs, 22 doubles, 25 home runs, 70 runs batted in, with a .262 average and a .765 OPS.
Mariners at Astros Betting Trends
Overall, in the series between Houston and Seattle, the Astros have won nine of the most recent 17 meetings. Only six of the last 20 games between Seattle and Houston went over the total.
Specifically at Houston, the Astros got the cash in four of their most recent six games against the Mariners. Only six of the last 18 games between the Mariners and Astros at Houston went over the total.
Mariners at Astros Bookmaker Best Bets
As mentioned earlier, Houston has been a more reliable betting value than Seattle. And this series has trended under the total.
Main Pick: Houston Astros
Over/Under Pick: Under the Total
Player Prop Picks: Jose Altuve Over the Hit Total
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