Cardinals vs. Mariners Prediction, Odds, Probable Pitchers and Prop Bets for Monday, Sept. 8

Betting odds, pick and prediction for the St. Louis Cardinals-Seattle Mariners matchup on Monday night.

Should bettors fade Seattle Mariners starter Bryan Woo tonight? / Stephen Brashear-Imagn Images

The Seattle Mariners are holding on to the final playoff spot in the American League entering Monday’s contest with the St. Louis Cardinals, who have won seven of their last 10 games. 

St. Louis is still 4.5 games out of a playoff spot in the National League, but it remains alive with just a few weeks left in the regular season.

On Monday, All-Star Bryan Woo (3.02 ERA) will get the ball for the Mariners against Miles Mikolas (4.89 ERA). Oddsmakers at the best betting sites have set the Mariners as massive favorites in this matchup.

Let’s dive into the odds, players to bet on in the prop market and my prediction for Monday’s action.  

Cardinals vs. Mariners Odds, Run Line and Total

Odds via DraftKings Sportsbook

Run Line

• Cardinals +1.5 (-115)
• Mariners -1.5 (-105)

Moneyline

• Cardinals: +186
• Mariners: -231

Total

• 7.5 (Over -110/Under -110)

Cardinals vs. Mariners Probable Pitchers

• St. Louis: Miles Mikolas (7-10, 4.89 ERA)
• Seattle: Bryan Woo (12-7, 3.02 ERA)

Cardinals vs. Mariners How to Watch

• Date: Monday, Sept. 8
• Time: 9:40 p.m. EST
• Venue: T-Mobile Park
• How to Watch (TV): ROOT Sports NW and FDSMW
• Cardinals record: 72-72
• Mariners record: 75-68

Cardinals vs. Mariners Best MLB Prop Bets

Mariners Best MLB Prop Bet

• Cal Raleigh to Hit a Home Run (+205)

Earlier today, I shared in SI Betting’s best home run picks – Daily Dinger – why Raleigh is worth a look against St. Louis: 

Seattle Mariners catcher Cal Raleigh has 53 long balls in the 2025 season, and he’s looking to add to that total against the St. Louis Cardinals and Miles Mikolas on Monday.

Mikolas has given up 24 home runs in 27 appearances this season, posting a 4.89 ERA in the process. Meanwhile, Raleigh has homered three times in the last week and 33 times this season against right-handed pitching.

It’s rare to see Ralegh at a number north of +200, and I like this spot for him since he’s started to heat up. The Mariners catcher is hitting .286 over his last six games, well above his season average of .243.

All season long, he’s been one of the most reliable players in this prop market, so I don’t plan on avoiding him in a favorable matchup. 

Cardinals vs. Mariners Prediction and Pick

My favorite bet in this game is a prop, as I don’t love either side at the current price. 

Prior to his last two starts, Woo had pitched at least six innings in every game this season, but he’s now fallen short of that target in back-to-back outings.

Overall, Woo has pitched into the seventh inning (and recorded an out) in 11 of his 27 outings in the 2025 season. So, I don’t think it’s crazy to fade him here against a Cardinals team that has won seven of its last 10 games.

Woo has thrown 100 pitches in just three outings all season, and he was taken out after just 84 pitches in his last start. While bettors have to lay some juice with this prop, I think the UNDER is the bet to make on Monday. 

Pick: Bryan Woo UNDER 18.5 Outs Recorded (-165 at DraftKings)

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Odds refresh periodically and are subject to change.

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