MLB Prediction: St. Louis Cardinals vs Seattle Mariners (Monday, September 8 at 09:40 PM ET)
Introduction
| Market / Trend | STL | SEA |
|---|---|---|
| Moneyline | +176 | -217 |
| Total (O/U) | 7.5 | |
| Run Line | +1.5 (-119) | -1.5 (-102) |
| Last 5 RPG | 3.2 | 7.6 |
| Record | 71–72 | 74–68 |
| Lines: BetMGM, BetOnline.ag, BetRivers, BetUS +6 more | ||
More MLB picks: St. Louis Cardinals · Seattle Mariners
Seattle enters this interleague matchup analysis against St. Louis with a strong offensive signal, averaging 7.6 runs per game across their last five outings. The Cardinals have gone 4-1 in that same stretch, but their scoring has lagged at just 3.2 runs per contest, creating a clear imbalance in recent production. This MLB prediction leans heavily toward Seattle Mariners’ ability to extend innings and push totals higher, while St. Louis Cardinals’ modest away form leaves them vulnerable against a lineup that thrives at home.
Game Time
Opening pitch at Monday, September 8 at 09:40 PM ET at T-Mobile Park, pitcher-friendly by profile.
Odds & Spread Line
- St. Louis Cardinals: +176
- Seattle Mariners: -217
Total: 7.5
- Run Line — St. Louis Cardinals: +1.5 (-119)
- Run Line — Seattle Mariners: -1.5 (-102)
Latest Team Records
St. Louis Cardinals: 71-72 (Win %: 0.497)
Seattle Mariners: 74-68 (Win %: 0.521)
Injury Report
St. Louis Cardinals are missing Giovanny Gallegos (Undisclosed), listed as Day-To-Day.
Seattle Mariners are missing Gregory Santos (Knee), listed as 60-Day-IL.
Key Player Stats
St. Louis Cardinals
- Willson Contreras: 0.254 AVG, 20 HR, 78 RBI
- Alec Burleson: 0.286 AVG, 16 HR, 60 RBI
- Ivan Herrera: 0.28 AVG, 14 HR, 54 RBI
Seattle Mariners
- Cal Raleigh: 0.242 AVG, 52 HR, 110 RBI
- Eugenio Suarez: 0.236 AVG, 43 HR, 106 RBI
- Julio Rodriguez: 0.265 AVG, 30 HR, 86 RBI
Team Analysis
St. Louis Cardinals
The Cardinals have pieced together a 4-1 record across their last five games, but with only 3.2 runs per game in that span, their offense has not matched their win-loss column. That type of production is unlikely to sustain against a power-driven Seattle lineup, especially with St. Louis carrying a 31-38 road record. Willson Contreras has been a valuable run producer, but the lack of consistent complementary support limits their ceiling in high-scoring environments.
Over the last 10 games, the Cardinals have gone 7-3 at 3.8 runs per game, a modest uptick but still below the pace needed to keep up with opponents averaging well over five runs. Alec Burleson and Ivan Herrera have chipped in, yet the road splits remain a liability when facing a team that thrives in its home park. If the scoring trend continues, St. Louis will struggle to match tempo against a Mariners side that has consistently pushed totals higher at home.
- Batting Average: 0.246
- Total Runs Scored: 618
- Home Runs: 136
- OBP: 0.314
- SLG: 0.382
- OPS: 0.696
- ERA: 4.28
- WHIP: 1.32
Away Record: 31-38 • Home Record: 41-34
Last 5 Games: 4-1 (3.2 RPG)
Last 10 Games: 7-3 (3.8 RPG)
Seattle Mariners
Seattle Mariners’ offense has surged, putting up 7.6 runs per game over their last five contests, even though the record sits at 2-3. That scoring output reveals their ability to generate instant offense, with Cal Raleigh and Eugenio Suarez delivering elite power numbers. At 41-27 at home, the Mariners have consistently leveraged their environment to outscore opponents, creating a clear betting edge in this spot.
Across the last 10 games, Seattle has gone 4-6 but still averaged 5.5 runs, showing that their losses have not stemmed from offensive stagnation. Julio Rodriguez remains a game-changer, and his production helps elevate the lineup’s overall consistency. The Mariners’ combination of home dominance and sustained scoring volume makes them the sharper side when evaluating the moneyline value.
- Batting Average: 0.241
- Total Runs Scored: 649
- Home Runs: 205
- OBP: 0.318
- SLG: 0.412
- OPS: 0.73
- ERA: 4.03
- WHIP: 1.26
Away Record: 34-41 • Home Record: 41-27
Last 5 Games: 2-3 (7.6 RPG)
Last 10 Games: 4-6 (5.5 RPG)
Head-to-Head History
No recent matchups between these teams in 2025.
Over/Under Trends
St. Louis Cardinals’ last 10 games have averaged 7.9 total runs, with 4 games that would have cleared today’s total of 7.5.
Seattle Mariners’ last 10 games have averaged 10.2 combined runs, with 6 games clearing the same number of 7.5.
Moneyline Betting Prediction
The Mariners’ home record of 41-27 combined with a scoring rate of 7.6 runs per game over their last five provides a clear edge over a Cardinals team that struggles to score consistently on the road. With power bats like Cal Raleigh and Eugenio Suarez driving production, Seattle Mariners’ lineup is positioned to overwhelm St. Louis and secure the win with authority.
We’re backing the Seattle Mariners — the read is consistent across metrics.
Over/Under Prediction
Recent five-game scoring: the Seattle Mariners are at 7.6 RPG and the St. Louis Cardinals at 3.2 — a useful baseline against the total.
These teams are combining for 10.8 runs per game recently — above the posted total of 7.5. That points toward the Over 7.5.
Bookmakers
Data pulled from: FanDuel, LowVig.ag, BetOnline.ag, Caesars, DraftKings, MyBookie.ag, BetUS, BetRivers, BetMGM, Bovada.
Parlamaz may earn affiliate commissions from links in this article.
MLB Predictions FAQ
How does Parlamaz make St. Louis Cardinals vs Seattle Mariners MLB predictions?
We use trusted data feeds and real-time odds to model each matchup. We weight the numbers that move lines—team form, matchup history, injuries, park factors, totals trends, and betting momentum—then compare our price to the market to find value. All signal, no noise. No paywalls.
How often are picks updated?
Daily. We update for confirmed lineups, injuries, and market moves. Check back near first pitch for final notes.
