Seattle Mariners vs. Houston Astros Picks and Prediction for Saturday, September 20, 2025
Use Code WWWC It’s the middle game of a critical three-game series between AL West foes on the diamond in the Lone Star State as the Seattle Mariners travel to face the Houston Astros Saturday night and we have you covered with our Mariners vs. Astros prediction. Seattle won the rubber game of a three-game set with the Royals on the road, prevailing 2-0 Thursday afternoon. Houston swept the Rangers at home, prevailing 5-2 in the finale Wednesday. This article was published prior to the conclusion of the opening game of the series at Daikin Park Friday night. Read more about this Mariners vs. Astros prediction! Don’t go down on strikes! Increase your bankroll with our MLB Betting Picks!
Mariners Battling for AL West Top Spot
Seattle won for the 11th time in 12 games as they took the rubber game of their three-game set against the Royals on Thursday. The Mariners entered Friday 84-69 and stood tied for first with the Astros for the top spot. They own the tiebreaker by virtue of a better division record, as the teams have split 10 meetings entering Friday. Against Kansas City, Seattle finished with five hits as Josh Naylor (run) was the only player with two. Luis Castillo (10-8) earned the win as he threw six scoreless innings, allowing three hits with no walks and three strikeouts. Andres Munoz worked a scoreless ninth, allowing one hit with no walks and three strikeouts, for his 36th save.
George Kirby is on the bump for the Mariners as he makes his 22nd start of the season in this contest. He is 9-7 with a 4.46 ERA, a 1.226 WHIP, 28 walks and 120 strikeouts over 115 innings of work this season. Kirby earned the win in his last start, which came at home against the Angels on Sunday. He threw 6.1 innings, allowing two runs on three hits with no walks and 14 strikeouts in an 11-2 Mariners victory. In his last three starts, Kirby is 1-1 with an 8.76 ERA, a 1.78 WHIP, two walks and 17 strikeouts over 12.1 innings of work. Kirby makes his ninth career start against the Astros in this contest. He is 3-1 with a 2.44 ERA, a 0.992 WHIP, five walks and 41 strikeouts over 44.1 innings of work against them. Kirby is 2-1 with a 3.42 ERA, a 1.063 WHIP, four walks and 23 strikeouts over 26.1 innings of work in five career starts at Daikin Park.
Houston Trying to Take AL West Lead
Houston won for the fifth time in six games as they finished a sweep of the Rangers by prevailing in the finale on Wednesday at home. The Astros entered Friday night 84-69 and were even with the Mariners for the top spot in the AL West. Due to tiebreakers, they held the second wild card spot, 2.5 games clear of Cleveland to remain in the playoff field. Against Texas, Houston finished with six hits as Jeremy Pena (two runs, RBI) and Carlos Correa (two runs) each had two. Jose Altuve (his 26th) and Pena (his 16th) each went deep in the victory for the Astros. Cristian Javier (2-3) earned the win as he threw six innings, allowing two runs on five hits with one walk and four strikeouts. Bryan King retired the four hitters he faced to record his second save.
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Framber Valdez is expected to get the ball for his 30th start of the year for the Astros in this contest. He is 12-10 with a 3.59 ERA, a 1.22 WHIP, 62 walks and 173 strikeouts over 180.1 innings of work on the year. Valdez took the loss in his last start, which came against the Braves on the road Sunday. He threw four innings, allowing five runs on six hits with four walks and two strikeouts in an 8-3 Houston defeat. In his last three starts, Valdez is 0-3 with a 7.88 ERA, a 1.56 WHIP, six walks and 15 strikeouts over 16 innings of work. Valdez makes his 19th career appearance, 17th start, against the Mariners in this contest. He is 7-3 with a 3.22 ERA, a 1.281 WHIP, 44 walks and 101 strikeouts over 100.2 innings of work. Valdez is 39-22 with a 3.07 ERA, a 1.163 WHIP, 183 walks and 573 strikeouts over 530.1 innings of work at Daikin Park in 93 career appearances, 83 starts.
Mariners vs. Astros Pick
Moneyline Pick for Mariners vs. Astros
- Mariners (4 units)
We’ve talked previously about how Seattle’s rotation has struggled on the road this season. Kirby is 5-3 with a 3.36 ERA at home but is 4-4 with a 5.74 ERA on the road over 53.3 innings of work on the year. He is coming off a stellar outing in his last start as he fanned 14 hitters en route to a win. Meanwhile, Houston is dealing with a double whammy as Yordan Alvarez was placed on the IL, taking a bat out of the lineup, and Valdez has sputtered of late. Since August 1, Valdez is 1-6 with a 6.41 ERA, a 1.576 WHIP, 18 walks and 32 strikeouts over 46.1 innings in his eight starts. He’s given up at least four runs in seven of those outings. As a result, you have to fade the Astros here and take the Mariners on the road here.
Over/Under Pick for Mariners vs. Astros
- Over (4 units)
Seattle has seen the over go 84-63-6 in their first 153 games of the year entering Friday night. The Mariners are 10th in the majors with 4.73 runs per game, a number that climbs to 5.09 runs per game on the road. They have an average total of 9.08 runs per game and that number rockets to 9.99 runs per game as the visiting team. Houston has seen the under post a 77-70-6 mark in their 153 games this season entering Friday. The Astros are tied for 21st in the majors in runs per game with 4.25 per contest, a number that falls to four runs per game at home. Their average total this season is 8.29 runs per game, though that slips to 8.23 runs per game at Daikin Park. Given Kirby’s road struggles and Valdez’s issues over the last six weeks or so, this game winds up over the total.
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