Kansas City Royals 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
Royals- Bobby Witt Jr.Batting1-4, 1 RBI
- Michael WachaPitching4.0 IP, 4 ER, 4 K
Diamondbacks- Randal GrichukBatting1-2, 1 HR, 2 RBI
- Ryne NelsonPitching7.0 IP, 1 ER, 5 K
Scoring summary
- 8Grichuk homered to right center (395 feet), Alexander scored.1–7
- 7McCann doubled to center, Gurriel Jr. scored.1–5
- 6Witt Jr. singled to right, Fermin scored, India to second.1–4
- 5Gurriel Jr. doubled to left, Smith scored and Perdomo scored.0–4
- 3Suárez singled to left, Smith scored, Naylor to third.0–2
- 3Naylor singled to center, Perdomo scored, Smith to third.0–1
The pick
Reconstructed from what was known before the game: the ratings at that point and the closing line.
Diamondbacks 55%
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
- ARI 55%
- ML KC +115 / ARI -135
- Pre-line forecast
- ARI 53%
- Elo + market-implied
- Elo ratings
- ARI 58%
- Ratings vs. market
- +2.4 pts
- ARI: Elo 57.7%, market 55.3%
- Fair odds
- ARI -124
- KC +124 · the forecast as odds, no margin
- Pregame projection
- KC 4.5 – 5.0 ARI
- Margin from the forecast, posted total 9.5
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 | KC | ARI | Why |
|---|---|---|---|
| Team rating | 1490 | 1511 | Elo entering the game; 1500 is league average |
| Home field | — | +18 | Worth 18 Elo in MLB |
| Starting pitchers | +2 | +16 | KC: Michael Wacha: team allows 0.10 fewer runs than with its usual starter (≈10 weighted starts) · ARI: Ryne Nelson: team allows 0.81 fewer runs than with its usual starter (≈10 weighted starts) |
| Elo ratings | ARI +54 Elo | ARI 57.7% | |
| Market-implied ratings | ARI 52.2% | Team strength as past closing lines priced it, same game context | |
| Pre-line forecast | ARI 53.0% | 15% Elo, 85% market-implied (log-odds blend) | |
| Forecast | ARI 55.3% | 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.
| KC | Stat | ARI |
|---|---|---|
| 30th of 303.4 | Runs scored | 5.23rd of 30 |
| 3rd of 303.7 | Runs allowed | 5.227th of 30 |
| 21st of 30−0.3 | Margin | 0.019th of 30 |
| 20th of 304–6 | Last 10 | 3–725th of 30 |
| 10th of 3022–23 | Road vs home | 22–2423rd of 30 |
| 16th of 301501 | Opponent Elo | 150111th of 30 |
| 21st of 301490 | Elo rating | 151114th 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 |  KC |  ARI |
|---|---|---|
| Run line | 44–45 | 44–44 |
| Last 10 | 6–4 | 3–7 |
| Favorite | 10–27 | 24–31 |
| Underdog | 34–18 | 20–13 |
| Overs–unders | 36–53 | 49–39 |
| Overs–unders, last 10 | 4–6 | 8–2 |
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
KC 3–4 ARI in their last 7 meetings; the forecast called 3 of 7.