Seattle Mariners at Kansas City Royals, 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 KC.
Game center
From the ESPN box score.
Top performers
Mariners- Josh NaylorBatting2-3
- Luis CastilloPitching6.0 IP, 0 ER, 3 K
Royals- Vinnie PasquantinoBatting1-4
- Stephen KolekPitching7.1 IP, 1 ER, 8 K
Scoring summary
- 8Crawford doubled to right, Robles scored.2–0
- 2Polanco doubled to right, Naylor scored.1–0
The pick
Reconstructed from what was known before the game: the ratings at that point and the closing line.
Mariners 52%
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
- SEA 52%
- ML SEA -120 / KC +100
- Pre-line forecast
- SEA 56%
- Elo + market-implied
- Elo ratings
- SEA 51%
- Ratings vs. market
- −1.4 pts
- SEA: Elo 50.7%, market 52.2%
- Fair odds
- SEA -109
- KC +109 · the forecast as odds, no margin
- Pregame projection
- SEA 4.8 – 4.7 KC
- 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 | SEA | KC | Why |
|---|---|---|---|
| Team rating | 1528 | 1496 | Elo entering the game; 1500 is league average |
| Home field | — | +18 | Worth 18 Elo in MLB |
| Starting pitchers | −5 | +4 | SEA: Luis Castillo: team allows 0.26 more runs than with its usual starter (≈10 weighted starts) · KC: Stephen Kolek: team allows 0.19 fewer runs than with its usual starter (≈8 weighted starts) |
| Elo ratings | SEA +5 Elo | SEA 50.7% | |
| Market-implied ratings | SEA 56.8% | Team strength as past closing lines priced it, same game context | |
| Pre-line forecast | SEA 55.9% | 15% Elo, 85% market-implied (log-odds blend) | |
| Forecast | SEA 52.2% | 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.
| SEA | Stat | KC |
|---|---|---|
| 10th of 304.8 | Runs scored | 3.928th of 30 |
| 17th of 304.4 | Runs allowed | 4.04th of 30 |
| 10th of 30+0.4 | Margin | −0.118th of 30 |
| 1st of 309–1 | Last 10 | 3–722nd of 30 |
| 20th of 3035–41 | Road vs home | 41–3619th of 30 |
| 20th of 301499 | Opponent Elo | 149723rd of 30 |
| 7th of 301528 | Elo rating | 149620th 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 |  SEA |  KC |
|---|---|---|
| Run line | 64–88 | 73–79 |
| Last 10 | 7–3 | 4–6 |
| Favorite | 32–65 | 25–43 |
| Underdog | 32–23 | 48–36 |
| Overs–unders | 85–67 | 67–85 |
| Overs–unders, last 10 | 7–3 | 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
SEA 12–7 KC in their last 19 meetings; the forecast called 12 of 19.