Seattle Mariners at Boston Red Sox
All Seattle Mariners predictions · All Boston Red Sox predictions
MLB · Monday, August 31, 2026 · 6:46 PM · Final: 8-9
Closing moneyline by book
The last price each book posted before first pitch — the prices this call could actually have been bet at. Best on each side is highlighted. In-game odds are deliberately excluded: once the game starts, the price tracks the score, not the matchup.
| Book | Seattle Mariners | Boston Red Sox |
|---|---|---|
| BetMGM | +135 | -160 |
| BetRivers | +133 | -157 |
| DraftKings | +142 | -153 |
| ESPN BET | +140 | -159 |
| Fanatics | +130 | -155 |
| FanDuel | +146 | -158 |
| Hard Rock Bet | +145 | -155 |
| Caesars | +145 | -155 |
Spread & total
Not part of the model's call. Collected from every book and graded in public so the prices can be checked — how spreads and totals have graded so far. The percent is what the price itself implies, vig removed.
| Spread by book | Mariners | Red Sox |
|---|---|---|
| BetMGM | +1.5 -170 | −1.5 +140 |
| BetRivers | +1.5 -167 | −1.5 +138 |
| DraftKings | +1.5 -164 | −1.5 +136 |
| ESPN BET | +1.5 -165 | −1.5 +140 |
| Fanatics | +1.5 -170 | −1.5 +140 |
| FanDuel | +1.5 -166 | −1.5 +138 |
| Hard Rock Bet | +1.5 -150 | −1.5 +140 |
| Caesars | +1.5 -155 | −1.5 +130 |
| Total by book | Over | Under |
|---|---|---|
| BetMGM | 7.5 -115 | 7.5 -105 |
| BetRivers | 7.5 -120 | 7.5 +100 |
| DraftKings | 7.5 -114 | 7.5 -105 |
| ESPN BET | 7.5 -115 | 7.5 -105 |
| Fanatics | 7.5 -115 | 7.5 -105 |
| FanDuel | 7.5 -115 | 7.5 -105 |
| Hard Rock Bet | 7.5 -110 | 7.5 +100 |
| Caesars | 7.5 -115 | 7.5 -105 |
Prediction markets vs the books
Every venue sells the same thing — a dollar if that side wins — at a different price. Implied cost per venue below; amber = the cheapest way to buy that side at the close.
| Venue | Seattle Mariners | Boston Red Sox |
|---|---|---|
| Books consensus fair, de-vigged | 40.5% | 59.5% |
| Best book price incl. vig | 40.7% | 60.5% |
| Kalshi contract price | 40.5% | 59.5% |
| Polymarket contract price | 40.5% | 59.5% |
| Markets average | 40.5% | 59.5% |
Contract prices exclude exchange trading fees (Kalshi ~1–2¢ midrange), which narrow small gaps. A venue meaningfully below the books consensus is either a bargain or an early opinion — the graded record decides which.