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
Red Sox- Roman AnthonyBatting1-4, 1 HR, 1 RBI
- Lucas GiolitoPitching6.0 IP, 0 ER, 10 K
Mariners- Jorge PolancoBatting1-4
- Logan GilbertPitching5.0 IP, 2 ER, 10 K
Scoring summary
- 3Toro reached on infield single to second, Duran scored.2–0
- 1Anthony homered to right center (391 feet).1–0
The pick
Reconstructed from what was known before the game: the ratings at that point and the closing line.
Mariners 60%
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 60%
- ML BOS +140 / SEA -165
- Pre-line forecast
- SEA 58%
- Elo + market-implied
- Elo ratings
- SEA 55%
- Ratings vs. market
- −5.3 pts
- SEA: Elo 54.7%, market 59.9%
- Fair odds
- SEA -149
- BOS +149 · the forecast as odds, no margin
- Pregame projection
- BOS 2.8 – 3.7 SEA
- Margin from the forecast, posted total 6.5
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 | 1505 | 1508 | Elo entering the game; 1500 is league average |
| Home field | — | +18 | Worth 18 Elo in MLB |
| Starting pitchers | −8 | +4 | BOS: Lucas Giolito: team allows 0.38 more runs than with its usual starter (≈10 weighted starts) · SEA: Logan Gilbert: team allows 0.21 fewer runs than with its usual starter (≈10 weighted starts) |
| Elo ratings | SEA +32 Elo | SEA 54.7% | |
| Market-implied ratings | SEA 58.2% | Team strength as past closing lines priced it, same game context | |
| Pre-line forecast | SEA 57.7% | 15% Elo, 85% market-implied (log-odds blend) | |
| Forecast | SEA 59.9% | Follows the market (vig removed): in testing, adding the ratings made it less accurate | |
Tale of the tape
This season 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. Opponent Elo: how strong the teams each has played are, 1st the toughest.
| BOS | Stat | SEA |
|---|---|---|
| 5th of 304.8 | Runs scored | 4.412th of 30 |
| 22nd of 304.5 | Runs allowed | 4.421st of 30 |
| 13th of 30+0.3 | Margin | 0.018th of 30 |
| 1st of 308–2 | Last 10 | 4–620th of 30 |
| 19th of 3015–19 | Road vs home | 19–1720th of 30 |
| 12th of 301501 | Opponent Elo | 149228th of 30 |
| 16th of 301505 | Elo rating | 150814th 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.
Against the line
How each team has done against the closing spread and total, coming into this game.
| This season |  BOS |  SEA |
|---|---|---|
| Run line | 37–36 | 29–41 |
| Last 10 | 6–4 | 2–8 |
| Favorite | 16–26 | 11–32 |
| Underdog | 21–10 | 18–9 |
| Overs–unders | 34–39 | 38–32 |
| Overs–unders, last 10 | 5–5 | 6–4 |
Against each game's closing line. Books set every line knowing these records: across 3,901 past games, the team with the better record against the spread so far that season covered 51.2%, short of the 52.4% a standard −110 bet needs, and over/under streaks held 48.0% of the time. They describe the past.
Head to head
BOS 8–8 SEA in their last 16 meetings; the forecast called 9 of 16.