Seattle Mariners vs Houston Astros Prediction, Odds and Picks for Today, 09/20/25

The Seattle Mariners and Houston Astros take center stage on Saturday night as they wrestle for control of the AL West. The Mariners won Friday’s game, 4-0, on the strength of elite pitching and 4 solo homers. The Mariners are the hottest team in baseball right now, winning 12 of their last 13 games, and bashing the heck out of the baseball most nights along the way. They now have a 1-game lead in the division, and I love their chances of leaving Houston with the advantage in the standings before closing the season with the Rockies and Dodgers. My Mariners vs Astros best bet is the Mariners on the money line.

Something is very wrong with Framber Valdez. He has struggled the entire second half, and while he has worked in a useful start here or there, it just seems like something is wrong with him. He is walking lots of guys, and he is giving up lots of homeruns. Most of the Seattle lineup has seen Valdez tons of times, and this doesn’t seem like a great spot for him to get right. George Kirby, on the other hand, is one of the anchors of the Mariner staff, and he is coming off a 14-strikeout effort earlier this week. It was a nice bounce-back from two short outings, and while Kirby isn’t in his best form, the current Astros lineup hasn’t had much career success against him. With Yordan Alvarez back on the IL, the Houston lineup is way too right-handed, and righties hit 40 points lower against Kirby than lefties. It’s a good spot for Kirby, and I look for him to hand off a lead to his bullpen. Give me the Mariners on Saturday.

Mariners vs Astros Prediction: Mariners ML (-105) available at the time of publishing. Playable at that number.

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