The Seattle Mariners, who have won three in a row and nine of their last 10, will go for the sweep on Sunday, Sept. 21 when they meet the Houston Astros on Sunday Night Baseball. First pitch on ESPN is set for 7 p.m. ET. The Mariners currently hold a two-game lead over the Astros in the AL West. Houston is tied with the Guardians in the AL Wild Card standings thanks to Cleveland’s 10-game winning streak.

Those interested in MLB betting and looking to make wagers on Mariners vs. Astros should check out the SportsLine Inside the Lines team model, which simulates every game 10,000 times. The model enters Week 26 of the 2025 MLB season a profitable 34-27 on top-rated MLB money line picks.

Logan Gilbert (5-6, 3.53 ERA) gets the nod for Seattle in the series finale. He’s allowed just three runs across his last two starts. Gilbert pitched against the Astros back in April, allowing one run in 5 2/3 innings in a no decision. The Astros are going with Jason Alexander (4-1, 4.04 ERA). Though Alexander has not gotten a decision in his last four starts, Houston has won all those games. The Astros have won the last nine games Alexander has started. In his last outing against the Rangers, the righty gave up three runs in 4 2/3 innings while striking out five. 

DraftKings Sportsbook has set Gilbert’s strikeouts line at 6.5 (Over -117, Under -109) and Alexander’s line is 4.5 (Over -104, Under -123). The SportsLine model likes the Over for both pitchers, projecting Alexander for 5.0 strikeouts and Gilbert for 6.6.

Cal Raleigh, who recently passed Ken Griffey Jr. for the Mariners single season home run record, is +258 to leave the park on Sunday. Seattle teammate Eugenio Suarez is +443 to go yard. Houston slugger Christian Walker is slightly ahead of Suarez to hit a home run at +426. Julio Rodriguez (+457) and Jorge Polanco (+491) round out the top five in the odds table. Josh Naylor is nearly even with Polanco at +492. 

The Mariners are -141 favorites (wager $141 to win $100) on the money line in the latest SportsLine consensus odds, while the Astros are +118 (wager $100 to win $118) underdogs. The total is set at 8. You can find the model’s latest projections and expert picks for Mariners vs. Astros at SportsLine.

Here are the Inside the Lines team’s model projections for Mariners vs. Astros on Sunday.

SEATTLE MARINERS at HOUSTON ASTROS | 9/21 | 7 p.m. ET

Money line
Pick: Mariners -141
Seattle wins in 57% of simulations

Run line
Pick: Astros +1.5 (-141)
Houston covers in 60% of simulations

Over/Under
Pick: Over 8
The Over hits in 51.8% of simulations

Projected score: Mariners 4.9, Astros 4.1