The Houston Astros and Seattle Mariners headline MLB’s return to action on Friday.
The pregame narrative: Houston’s Brandon Walter (3.98 ERA) starts opposite Seattle’s Luis Castillo (3.41 ERA) in what has the makings of a pitching duel. The Mariners can gain some important ground in the AL West if they come out of this series with a good result.
Check out my Astros vs. Mariners predictions, featuring Walter and Cal Raleigh.
Astros vs. Mariners predictions
Parlay: Under 8.5 runs | Walter over 4.5 Ks | Raleigh 1+ hit (+310)
Under 8.5 runs (-162): With the all-star break in the rear view mirror, I’ll opt to side with pitching on the first day back.
While the time off is more typical for a starting pitcher, hitters don’t get much time off during the regular season, and there could be some rust to overcome from the only lengthy break.
Plus, both starters are nasty when they’re pitching well.
I’ll write more about Walter later, so let’s focus on Castillo for this portion. Heading into the all-star festivities, the righty gave up just four runs over his final three starts (18.0 innings pitched).
Overall, he’s given up three or fewer earned runs in 12 of his past 15 starts, pitching five or more innings in all of those games.
That gives him an incredible floor to work with as a starter.
Castillo has started two games against the Astros this year. Both games stayed under 8.5 runs.
MLB SGP legs
Walter over 4.5 Ks (-159): Now, let me turn my attention to Houston’s starter.
Walter has been better than expected in his first season with the Astros, boasting a 4.01 FIP and 1.01 WHIP through seven starts.
Across those 40.2 IP, he has 40 Ks while allowing just two walks. He doesn’t give up free passes, meaning basically every at-bat ends with contact or a strikeout.
The left-handed pitcher has cleared this mark in six of his seven starts this season.
Additionally, the Mariners strike out the fourth most times per game in the majors (8.82).
Raleigh 1+ hit (-205): The AL MVP candidate has an incredibly high 14.9% walk-rate (99th-percentile), which usually works against him on this market.
But as I mentioned, it’s rare for Walter to give a free pass to anyone, so I’m expecting Raleigh to have a few chances to make contact.
In fact, Walter’s 1.2% walk rate ranks in the 100th percentile.
And it makes sense to back Raleigh off the back of his win at the Home Run Derby. He continues to build momentum as he chases the AL home run record in the second half of the season.
The slugging catcher has a 98th percentile barrel rate (20.0%), per Baseball Savant, so it’s a dangerous proposition to throw him a lot of strikes.
But that’s Walter’s forte, and I don’t expect that to change even for Raleigh, which has me excited for his potential as a hitter tonight.
Astros vs. Mariners predictions made at 10:13 a.m. on 07/18/2025.
Spencer is a true sports junkie. A graduate of the Sports Journalism program at Centennial College, he first joined NorthStar Gaming as an intern in 2023. He is now a contributing writer. He loves finding the edge to bet on in all sports but has a deep passion for the NBA and UFC. Previous stops include Sportsnet.