bayesRatings

Red Sox at Mariners

MLB · Sunday, Jun 21 · 3:10 PM CT · T-Mobile Park · Final BOS 1 – SEA 3
← MLB / Jun 21

Final Box Score

from the game summary
Team123456789THE
BOS001000000150
SEA01001100361
Team box
BOS·SEA
5
hits
6
1
home runs
1
2
walks
3
13
strikeouts
4
109
pitches thrown
129
0
errors
1
Top hitters
PlayerTeamH-ABRHRRBI
Dominic CanzoneSEA1-3112
Nate EatonBOS1-2111
Caleb DurbinBOS2-3000
Cole YoungSEA1-3001
Ceddanne RafaelaBOS1-4000
Mickey GasperBOS1-3000
Pitchers
PitcherTeamIPHERBBK
Payton Tolle (L)BOS6.06322
Logan Gilbert (W)SEA6.13128
Andres Munoz (S)SEA1.01002

For context, not in our forecast.

Game Flow

score margin
SEA +3
BOS +3
123456789
largest lead: SEA 2 · BOS 0lead changes: 0

For context, not in our forecast.

Final · our forecast was BOS 47%, SEA 53% · Updated Jun 21

Expected margin
Even
Expected score
SEA 4.1 – 3.8 BOS
Expected total
7.9
Red SoxThe matchupMariners
+111Our fair odds−111
3.8Expected runs4.1
+0.01Power rating+0.04
4.0Runs / game4.1
4.0Allowed / game3.9
8.2Hits / game7.7
0.85Home runs / game1.24
2.9Walks drawn / game3.4
31−43Season record39−39
4−6Last 103−7

Prediction markets

Kalshi · Polymarket US · ProphetX · Novig
BOS chance · SEA chance
Our model fair47.5%52.5%
Kalshi48.7%56.7%
Polymarket USno two-sided price
ProphetXno two-sided price
Novigno two-sided price
Full price table
TeamOur modelfairKalshipre-game · 3:10 PM CTPolymarket US ProphetX Novig 
Moneyline
BOSBoston Red Sox+11147%+10548.7%———
SEASeattle Mariners−11153%−13156.7%———
Spreadabout even
BOSBoston Red Sox+0.3our margin————
SEASeattle Mariners−0.3our margin————
Totalwe expect 7.9
Over7.9our total————
Under7.9our 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: 2%Boston Red Sox by 5 runs: 4%Boston Red Sox by 4 runs: 5%Boston Red Sox by 3 runs: 7%Boston Red Sox by 2 runs: 10%Boston Red Sox by 1 run: 15%Seattle Mariners by 1 run: 15%Seattle Mariners by 2 runs: 11%Seattle Mariners by 3 runs: 8%Seattle Mariners by 4 runs: 6%Seattle Mariners by 5 runs: 4%Seattle Mariners by 6 runs: 3%Seattle Mariners by 7 runs: 2%Seattle Mariners by 8 runs: 1%Seattle Mariners by 9 runs: 1%Seattle Mariners by 10 runs: 1%Seattle Mariners by 11 runs: <1%Seattle Mariners by 12 runs: <1%
← BOS wins bySEA wins by →
Seattle Mariners wins by 2 or more37%
Seattle Mariners wins by 3 or more27%
Boston Red Sox wins by 2 or more32%
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

7.9 expected
1 runs: 2%2 runs: 2%3 runs: 8%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 7.548%
Total over 9.530%
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
BOSPayton Tolle SP · last 3 starts: 17.0 IP, 3.71 ERA, 14 Kstarted
SEALogan Gilbert SP · last 3 starts: 18.1 IP, 2.45 ERA, 23 Kstarted

Starting pitchers are part of our forecast.

Rest and Schedule

before this game
BOS·SEA
Jun 20 at SEA
last game
Jun 20 vs BOS
0 days
days of rest
0 days
6
games in last 7 days
6
3rd straight road game
home / road
6th straight home game

For context, not in our forecast.

Team Comparison

2026 season · box-score averages from 74+ games
BOS·SEA
+0.01
rating (0 = average)
+0.04
4.0
runs / game
4.1
4.0
runs allowed / game
3.9
31−43
season record
39−39
12−25
home record
21−19
19−18
away record
18−20
W2
streak
L2
4−6
last 10
3−7
8.2
hits / game
7.7
0.85
home runs / game
1.24
2.9
walks drawn / game
3.4
8.3
batter strikeouts / game
8.5
8.4
pitcher strikeouts / game
8.7
0.47
errors / game
0.45

Rating Trend

BOS · SEA · 88 days
Boston Red SoxSeattle Mariners
Rating (0 = average team)

Head to Head

last 10 meetings · SEA 4−6
Jun 20at SEABOS 5 − 1
Jun 19at SEABOS 6 − 2
Jun 18, 2025at SEABOS 3 − 1
Jun 17, 2025at SEASEA 8 − 0
Jun 16, 2025at SEABOS 2 − 0
Apr 24, 2025at BOSSEA 4 − 3
Apr 23, 2025at BOSSEA 8 − 5
Apr 22, 2025at BOSBOS 8 − 3
Jul 31, 2024at BOSBOS 3 − 2
Jul 30, 2024at BOSSEA 10 − 6

BOS · Last 10

4−6 · streak W2
Jun 20at SEA5 − 1W
Jun 19at SEA6 − 2W
Jun 18vs TOR3 − 4L
Jun 17vs TOR0 − 3L
Jun 16vs TOR1 − 6L
Jun 14vs TEX4 − 6L
Jun 13vs TEX6 − 3W
Jun 12vs TEX10 − 1W
Jun 10at TB5 − 7L
Jun 9at TB3 − 4L

SEA · Last 10

3−7 · streak L2
Jun 20vs BOS1 − 5L
Jun 19vs BOS2 − 6L
Jun 18vs BAL3 − 0W
Jun 17vs BAL3 − 5L
Jun 16vs BAL3 − 1W
Jun 14at WSH1 − 10L
Jun 13at WSH3 − 8L
Jun 12at WSH10 − 2W
Jun 11at BAL5 − 7L
Jun 10at BAL2 − 7L