San Francisco Giants at Arizona Diamondbacks, MLB forecast
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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
Giants- Casey SchmittBatting1-4, 1 HR, 1 RBI
- Tyler MahlePitching5.0 IP, 6 ER, 6 K
Diamondbacks- Ketel MarteBatting3-3, 1 HR, 2 RBI
- Merrill KellyPitching6.0 IP, 3 ER, 4 K
Scoring summary
- 5Perdomo doubled to right, Marte scored and Waldschmidt scored.3–6
- 5Vargas grounded out to first, Tawa scored, Marte to second, Waldschmidt to third.3–4
- 4Gilbert singled to right, Chapman scored, Susac to second.3–3
- 3Marte homered to center (415 feet), Waldschmidt scored.2–3
- 2Eldridge doubled to left, Chapman scored.2–1
- 1Perdomo hit sacrifice fly to center, Marte scored.1–1
- 1Schmitt homered to left (369 feet).1–0
The pick
Reconstructed from what was known before the game: the ratings at that point and the closing line.
Diamondbacks 51%
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 51%
- ML SF -107 / ARI -112
- Pre-line forecast
- ARI 54%
- Elo + market-implied
- Elo ratings
- ARI 56%
- Ratings vs. market
- +5.8 pts
- ARI: Elo 56.4%, market 50.5%
- Fair odds
- ARI -102
- SF +102 · the forecast as odds, no margin
- Pregame projection
- SF 4.2 – 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 | SF | ARI | Why |
|---|---|---|---|
| Team rating | 1485 | 1508 | Elo entering the game; 1500 is league average |
| Home field | — | +18 | Worth 18 Elo in MLB |
| Starting pitchers | −2 | +2 | SF: Tyler Mahle: team allows 0.10 more runs than with its usual starter (≈10 weighted starts) · ARI: Merrill Kelly: team allows 0.09 fewer runs than with its usual starter (≈10 weighted starts) |
| Elo ratings | ARI +45 Elo | ARI 56.4% | |
| Market-implied ratings | ARI 53.8% | Team strength as past closing lines priced it, same game context | |
| Pre-line forecast | ARI 54.2% | 15% Elo, 85% market-implied (log-odds blend) | |
| Forecast | ARI 50.5% | 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.
| SF | Stat | ARI |
|---|---|---|
| 30th of 303.5 | Runs scored | 4.611th of 30 |
| 15th of 304.5 | Runs allowed | 4.723rd of 30 |
| 26th of 30−1.0 | Margin | −0.115th of 30 |
| 14th of 305–5 | Last 10 | 7–34th of 30 |
| 22nd of 3010–17 | Road vs home | 13–86th of 30 |
| 1st of 301512 | Opponent Elo | 15058th of 30 |
| 22nd of 301485 | 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 |  SF |  ARI |
|---|---|---|
| Run line | 23–26 | 28–19 |
| Last 10 | 4–6 | 7–3 |
| Favorite | 6–8 | 10–11 |
| Underdog | 17–18 | 18–8 |
| Overs–unders | 21–25–3 | 22–21–4 |
| Overs–unders, last 10 | 5–5 | 4–6 |
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
SF 18–23 ARI in their last 41 meetings; the forecast called 27 of 41.