Boston Red Sox at Seattle Mariners, MLB forecast
Win probability
Starts from the pregame forecast, then moves with the score and the time left after each inning. Above the line favors SEA.
Game center
From the ESPN box score.
Top performers
- Tyler O'NeillBatting1-4
- Nick PivettaPitching6.0 IP, 1 ER, 10 K
- J.P. CrawfordBatting1-3, 1 HR, 1 RBI
- George KirbyPitching6.2 IP, 0 ER, 8 K
Scoring summary
- 6
Crawford homered to right (381 feet).0–1 - 6
Pitch 2 : Ball In Play0–1 - 6
Pitch 1 : Strike 1 Foul0–0
The pick
Reconstructed from what was known before the game: the ratings at that point and the closing line.
Mariners 57%
Forecast Elo ratings alone
How often that comes true: MLB favorites the forecast gave 55–60% have won 55.5% of 2,596 graded games.
- Market
- SEA 57%
- ML BOS +125 / SEA -150
- Pre-line forecast
- SEA 54%
- Elo + market-implied
- Elo ratings
- SEA 54%
- Ratings vs. market
- −3.7 pts
- SEA: Elo 53.7%, market 57.4%
- Fair odds
- SEA -135
- BOS +135 · the forecast as odds, no margin
- Pregame projection
- BOS 3.2 – 3.8 SEA
- Margin from the forecast, posted total 7
How the number is built
Elo inputs in rating points (higher favors that team; 25–28 Elo is about a point of spread in football and basketball), then how the pieces combine.
| Factor | BOS | SEA | Why |
|---|---|---|---|
| Team rating | 1497 | 1520 | Elo entering the game; 1500 is league average |
| Home field | — | +18 | Worth 18 Elo in MLB |
| Starting pitchers | +20 | +5 | BOS: Nick Pivetta: team allows 0.99 fewer runs than with its usual starter (≈8 weighted starts) · SEA: George Kirby: team allows 0.27 fewer runs than with its usual starter (≈10 weighted starts) |
| Elo ratings | SEA +26 Elo | SEA 53.7% | |
| Market-implied ratings | SEA 54.5% | Team strength as past closing lines priced it, same game context | |
| Pre-line forecast | SEA 54.4% | 15% Elo, 85% market-implied (log-odds blend) | |
| Forecast | SEA 57.4% | Follows the market (vig removed): in testing, adding the ratings made it less accurate | |
Tale of the tape
Last season (2023) coming into the game, regular season, each number with its league rank (the longer the bar, the higher). Home and road: the host's record at home against the visitor's on the road.
| BOS | Stat | |
|---|---|---|
| 11th of 304.8 | Runs scored | 4.712th of 30 |
| 21st of 304.8 | Runs allowed | 4.13rd of 30 |
| 14th of 300.0 | Margin | +0.69th of 30 |
| 26th of 303–7 | Last 10 | 4–616th of 30 |
| 16th of 3039–42 | Road vs home | 45–3610th of 30 |
Rating history
Each team's Elo over the last two seasons. Hover or drag to compare on any date.
Recent form
Last five results, and whether the forecast hit.
Head to head
BOS 4–3 SEA in their last 7 meetings; the forecast called 4 of 7.



