Houston Astros vs Seattle Mariners Prediction, Odds and Picks for Friday, 07/18/25

The AL West launches into the season’s second stanza with the Houston Astros going up against the Seattle Mariners. The Astros currently lead the division thanks in large part to an impressive winning streak a few weeks ago. They did, however, stumble across the finish line before the break — losing 5 of 6 to the Guardians and Rangers. The Mariners, on the other hand, closed the first half with a sweep on the road against the best team in the league over the first half, taking 3 from the Tigers. They did it with tons of scoring, too, especially powered by Home Run Derby champion Cal Raleigh (it’s enough with the nickname already, though, as it got run into the ground by the networks this week). I love this spot for the Mariners, and my Astros vs Mariners best bet is Seattle on the money line.

Luis Castillo takes the hill for the Mariners. If you have followed Castillo’s career, he is a second half darling. Often, if we take only the second half of the season, he is among the best pitchers in the league. I love that trend, and I am backing it on Friday. He will face Brandon Walter. Walter has made 7 starts — 5 of them have been good, 2 have been ugly. He has given up a ton of homers, too, which makes this a good Raleigh day. Moreover, the Mariners are seventh in the league in slugging vs LHP, and if they get a lead, their bullpen is also strong. I think this game sets up as well as any for the Mariners, especially when they closed the first half swing hot like they were. Here’s hoping they didn’t cool off in Atlanta.

Astros vs Mariners prediction: Seattle ML (-135) available at time of publishing. Playable at that number.

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