The Seattle Mariners are -120 favorites with top pitching prospect Kade Anderson slated to make his MLB debut.
Given the discrepancy between how the two teams have hit lefties, my Cubs vs. Mariners predictions and MLB picks believe the value lies with Chicago.
Who will win Cubs vs Mariners today: Cubs moneyline (+100)
David Peterson is quietly pitching well. He's worked 23 1/3 innings the past month, posting a 2.70 ERA with solid indicators (3.48 xFIP, 3.56 FIP). That is miles ahead of where he’s been.
He’s in a good spot to keep building vs. the Seattle Mariners, who've hit .214 with a .288 wOBA against lefties over the last month.
The Chicago Cubs lead the majors in OPS, ISO, and slot second in wOBA over the same span. Slowing them down will be a tall order for Kade Anderson in his debut.
Back Chicago to -115.
COVERS INTEL: The Cubs lead the league in OBP and OPS against left-handed pitching, leading to a strong 24-13 record when facing southpaw starters.
Cubs vs Mariners Over/Under pick: Under 7.5 (-110)
Peterson’s ERA sits at 5.26 this season but drops to 4.00 in "pitcher-friendly" conditions, and that’ll be the case in Seattle tonight.
Factor in that he’s in the best form of the season, and taking on a weak offense, and it’s a good spot for him to limit runs.
It’ll be tough to fully neutralize a strong Cubs offense, but Anderson should be able to prevent a ceiling performance. Their Achilles heel the last 30 days is a 25.3 K%, and Anderson possesses high-end strikeout upside.
I envision a 4-2 type of game, and see value in the Under to -120.
Cubs vs Mariners home run prediction: Seiya Suzuki (+365)
Seiya Suzuki possesses real pop against southpaws. He ranks in the 89th percentile in xSLG, the 91st percentile in ISO, and the 93rd in xwOBA.
He is consistently making powerful contact, and his ability to draw walks at a high rate — and play with real discipline — allows him to hang in at-bats and wait for the right opportunity to strike.
His OPS vs. lefties sits at 1.100 since July 1, putting him in the same range as NL MVP favorite Pete Crow-Armstrong.
Play to +350.
- ML/RL bets: 86-78, -10.20 units
- Over/Under bets: 85-73-6, +1.22 units
Cubs vs Mariners weather
Temperatures in the mid 70s are expected with slight winds blowing out. Neutral impact on the offenses.
Cubs vs Mariners odds
- Moneyline: Cubs +100 | Mariners -120
- Run line: Cubs +1.5 (-200) | Mariners -1.5 (+165)
- Over/Under: Over 8 (+100) | Under 8 (-120)
Cubs vs Mariners trend
Chicago has hit the moneyline in 21 of the last 30 away games (+11.55 units, 32% ROI). Find more MLB betting trends for Cubs vs. Mariners.
How to watch Cubs vs Mariners and game info
| Location | T-Mobile Park, Seattle, WA |
| Date | Saturday, August 22, 2026 |
| First pitch | 10:10 p.m. ET |
| TV | FOX |
| Cubs starting pitcher | David Peterson (7-7, 5.29 ERA) |
| Mariners starting pitcher | Kade Anderson (MLB Debut) |
Cubs vs Mariners latest injuries
Odds are correct at the time of publishing and are subject to change.
Not intended for use in MA.
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