Boston Red Sox at Arizona Diamondbacks, MLB forecast
You didn't pick this one.
Win probability
Starts from the pregame forecast, then moves with the score and the time left after each inning. Above the line favors ARI.
Game center
From the ESPN box score.
Top performers
Red Sox- Trevor StoryBatting2-3, 1 RBI
- Brayan BelloPitching6.0 IP, 3 ER, 2 K
Diamondbacks- Gabriel MorenoBatting2-4, 1 RBI
- Ryne NelsonPitching6.0 IP, 1 ER, 3 K
Scoring summary
- 9Narváez singled to right, Sogard scored.7–4
- 9Sogard doubled to center, Eaton scored and González scored.6–4
- 7Lawlar singled to left, Thomas scored, Locklear to second.4–4
- 7Lowe scored on error and Hamilton scored on error, Wong safe at first on throwing error by third baseman Lawlar, Wong safe at second on error.4–3
- 7Hamilton singled to center, Story scored, Lowe to third.2–3
- 6Moreno doubled to right, Carroll scored.1–3
- 4Carroll scored on Bello wild pitch.1–2
- 4Carroll scored on Bello wild pitch.1–2
- 4Story singled to right, Bregman scored.1–1
- 2Alexander singled to center, Moreno scored.0–1
The pick
Reconstructed from what was known before the game: the ratings at that point and the closing line.
Diamondbacks 50%
Forecast Elo ratings alone
How often that comes true: MLB favorites the forecast gave 50–55% have won 52.7% of 2,871 graded games.
- Market
- ARI 50%
- ML BOS -110 / ARI -110
- Pre-line forecast
- ARI 49%
- Elo + market-implied
- Elo ratings
- ARI 51%
- Ratings vs. market
- +1.1 pts
- ARI: Elo 51.1%, market 50.0%
- Fair odds
- ARI -100
- BOS -100 · the forecast as odds, no margin
- Pregame projection
- BOS 4.3 – 4.3 ARI
- Margin from the forecast, posted total 8.5
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 | ARI | Why |
|---|---|---|---|
| Team rating | 1525 | 1519 | Elo entering the game; 1500 is league average |
| Home field | — | +18 | Worth 18 Elo in MLB |
| Starting pitchers | +3 | −1 | BOS: Brayan Bello: team allows 0.14 fewer runs than with its usual starter (≈10 weighted starts) · ARI: Ryne Nelson: team allows 0.05 more runs than with its usual starter (≈10 weighted starts) |
| Elo ratings | ARI +8 Elo | ARI 51.1% | |
| Market-implied ratings | BOS 51.3% | Team strength as past closing lines priced it, same game context | |
| Pre-line forecast | BOS 50.9% | 15% Elo, 85% market-implied (log-odds blend) | |
| Forecast | ARI 50.0% | 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 | ARI |
|---|---|---|
| 7th of 304.9 | Runs scored | 4.95th of 30 |
| 14th of 304.3 | Runs allowed | 4.723rd of 30 |
| 6th of 30+0.6 | Margin | +0.215th of 30 |
| 12th of 305–5 | Last 10 | 8–21st of 30 |
| 12th of 3034–37 | Road vs home | 38–3317th of 30 |
| 14th of 301501 | Opponent Elo | 149625th of 30 |
| 8th of 301525 | Elo rating | 151910th 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 |  ARI |
|---|---|---|
| Run line | 74–69 | 75–68 |
| Last 10 | 3–7 | 9–1 |
| Favorite | 36–50 | 32–46 |
| Underdog | 38–19 | 43–22 |
| Overs–unders | 72–71 | 72–71 |
| Overs–unders, last 10 | 5–5 | 3–7 |
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 2–6 ARI in their last 8 meetings; the forecast called 1 of 8.