bayesRatings

Red Sox at Royals

MLB · Wednesday, May 20 · 6:40 PM CT · Kauffman Stadium · Final BOS 4 – KC 3
← MLB / May 20

Final Box Score

from the game summary
Team123456789THE
BOS0200002004111
KC100020000381
Team box
BOS·KC
11
hits
8
1
home runs
2
3
walks
1
10
strikeouts
8
134
pitches thrown
176
1
errors
1
Top hitters
PlayerTeamH-ABRHRRBI
Jarren DuranBOS2-5112
Salvador PerezKC3-4111
Elias DiazKC1-3112
Willson ContrerasBOS3-4100
Nick SogardBOS1-3001
Jac CaglianoneKC2-4000
Pitchers
PitcherTeamIPHERBBK
Connelly Early (W)BOS6.16315
Aroldis Chapman (S)BOS1.01001
Michael WachaKC6.06128
Steven Cruz (L)KC0.22201

For context, not in our forecast.

Game Flow

score margin
KC +3
BOS +3
123456789
largest lead: KC 1 · BOS 1lead changes: 3

For context, not in our forecast.

Final · our forecast was BOS 50%, KC 50% · Updated May 20

Expected margin
Even
Expected score
BOS 3.9 – 3.9 KC
Expected total
7.8
Red SoxThe matchupRoyals
−102Our fair odds+102
3.9Expected runs3.9
+0.05Power rating−0.05
3.7Runs / game3.9
3.9Allowed / game4.5
8.0Hits / game7.8
0.73Home runs / game0.94
3.1Walks drawn / game3.5
21−27Season record20−29
5−5Last 102−8

Prediction markets

Kalshi · Polymarket US · ProphetX · Novig
BOS chance · KC chance
Our model fair50.4%49.6%
Kalshi50.7%54.7%
Polymarket USno two-sided price
ProphetXno two-sided price
Novigno two-sided price
Full price table
TeamOur modelfairKalshipre-game · 6:40 PM CTPolymarket US ProphetX Novig 
Moneyline
BOSBoston Red Sox−10250%−10350.7%———
KCKansas City Royals+10250%−12154.7%———
Spreadabout even
BOSBoston Red Sox−0.1our margin————
KCKansas City Royals+0.1our margin————
Totalwe expect 7.8
Over7.8our total————
Under7.8our total————

These are each venue’s last prices before the start (Kalshi’s moneyline: its pre-game close). Odds are the price to buy that side now, taker fee included; the small percent is the implied chance of that same price. Highlighted is the best price in the row among venues on the same line. — means not listed (hover or tap for why). A market price is not the true chance of winning.

Margin range

Even game expected
Boston Red Sox by 12 runs: <1%Boston Red Sox by 11 runs: <1%Boston Red Sox by 10 runs: 1%Boston Red Sox by 9 runs: 1%Boston Red Sox by 8 runs: 1%Boston Red Sox by 7 runs: 2%Boston Red Sox by 6 runs: 3%Boston Red Sox by 5 runs: 4%Boston Red Sox by 4 runs: 6%Boston Red Sox by 3 runs: 7%Boston Red Sox by 2 runs: 11%Boston Red Sox by 1 run: 15%Kansas City Royals by 1 run: 16%Kansas City Royals by 2 runs: 10%Kansas City Royals by 3 runs: 7%Kansas City Royals by 4 runs: 5%Kansas City Royals by 5 runs: 4%Kansas City Royals by 6 runs: 3%Kansas City Royals by 7 runs: 2%Kansas City Royals by 8 runs: 1%Kansas City Royals by 9 runs: 1%Kansas City Royals by 10 runs: <1%Kansas City Royals by 11 runs: <1%Kansas City Royals by 12 runs: <1%
← BOS wins byKC wins by →
Boston Red Sox wins by 2 or more36%
Boston Red Sox wins by 3 or more25%
Kansas City Royals wins by 2 or more34%
Decided by one run31%

Centered on the expected margin above; shape from each team's expected runs, with ties after nine settled as one-run games, matched to 14,698 past MLB games.

Total range

7.8 expected
1 runs: 3%2 runs: 2%3 runs: 9%4 runs: 6%5 runs: 13%6 runs: 8%7 runs: 13%8 runs: 8%9 runs: 10%10 runs: 6%11 runs: 7%12 runs: 4%13 runs: 4%14 runs: 2%15 runs: 2%16 runs: 1%17 runs: 1%18 runs: 1%19 runs: <1%20 runs: <1%21 runs: <1%
Total runs, both teams
Total over 5.568%
Total over 7.547%
Total over 9.529%
Total from 6 to 939%

Centered on the expected total above; shape from each team's expected runs, with ties after nine settled as one-run games, matched to 14,698 past MLB games.

Starting Pitchers

from the box score
BOSConnelly Early SP · last 3 starts: 16.0 IP, 3.94 ERA, 17 Kstarted
KCMichael Wacha SP · last 3 starts: 20.0 IP, 2.25 ERA, 14 Kstarted

Starting pitchers are part of our forecast.

Rest and Schedule

before this game
BOS·KC
May 19 at KC
last game
May 19 vs BOS
0 days
days of rest
0 days
7
games in last 7 days
7
6th straight road game
home / road
3rd straight home game

For context, not in our forecast.

Team Comparison

2026 season · box-score averages from 48+ games
BOS·KC
+0.05
rating (0 = average)
−0.05
3.7
runs / game
3.9
3.9
runs allowed / game
4.5
21−27
season record
20−29
8−14
home record
13−12
13−13
away record
7−17
W2
streak
L2
5−5
last 10
2−8
8.0
hits / game
7.8
0.73
home runs / game
0.94
3.1
walks drawn / game
3.5
8.4
batter strikeouts / game
8.2
8.2
pitcher strikeouts / game
8.3
0.46
errors / game
0.37

Rating Trend

BOS · KC · 56 days
Boston Red SoxKansas City Royals
Rating (0 = average team)

Head to Head

last 10 meetings · KC 3−7
May 19at KCBOS 7 − 1
May 18at KCBOS 3 − 1
Aug 6, 2025at BOSKC 7 − 3
Aug 5, 2025at BOSBOS 6 − 2
Aug 4, 2025at BOSBOS 8 − 5
May 11, 2025at KCBOS 3 − 1
May 10, 2025at KCBOS 10 − 1
May 9, 2025at KCKC 2 − 1
Aug 7, 2024at KCKC 8 − 4
Aug 6, 2024at KCBOS 6 − 5

BOS · Last 10

5−5 · streak W2
May 19at KC7 − 1W
May 18at KC3 − 1W
May 17at ATL1 − 8L
May 16at ATL3 − 2W
May 15at ATL2 − 3L
May 14vs PHI1 − 3L
May 13vs PHI3 − 1W
May 12vs PHI1 − 2L
May 10vs TB1 − 4L
May 8vs TB2 − 0W

KC · Last 10

2−8 · streak L2
May 19vs BOS1 − 7L
May 18vs BOS1 − 3L
May 17at STL2 − 0W
May 16at STL2 − 4L
May 15at STL4 − 5L
May 14at CHW2 − 6L
May 13at CHW5 − 6L
May 12at CHW5 − 6L
May 10vs DET3 − 6L
May 9vs DET5 − 1W