BOS vs SEA prediction for June 21, 2026: Our Monte Carlo simulation ran 10,000 game iterations and projects SEA 3.2 - BOS 3.6. BOS is favored with a 51.3% win probability. The run line is -1.5 and the total is 6.5. Model projects 6.7 total runs.
SEA
3.2
Projected Score
VS
O/U 6.5
BOS
3.6
Projected Score
Win Probability
SEABOS
-1.5
Run Line (SEA)
6.5
Total Line
10,000
Simulations
Calibrated accuracy at this confidence: 55.1% (2,497 games)
Projected Runs Range 10th – 90th percentile
BOS
246
SEA
135
Projected
SEA 3.2 — BOS 3.6
Actual
SEA 3 — BOS 1
Starting Pitcher Matchup
Payton Tolle L
BOS
FF49%96 mph22% whiff
SI23%95 mph11% whiff
FC16%88 mph23% whiff
Logan Gilbert R
SEA
FF34%96 mph18% whiff
SL24%86 mph36% whiff
FS15%81 mph39% whiff
Weather Impact
T-Mobile Park
70°F7 mph windRoof: retractable
HR: 0.987 Total: 0.991
5mph in
Bullpen Comparison
BOS
3.90ERA
4.18FIP
9.00K/9
3.45BB/9
1.30WHIP
SEA
3.37ERA
3.72FIP
8.85K/9
3.64BB/9
1.33WHIP
Betting Edges
RUN_LINE AWAY +1.5
-37.2% EV
-233
F5_ML HOME
-21.4% EV
-135
RUN_LINE HOME -1.5
-15.6% EV
+188
F5_ML AWAY
+14.1% EV
+108
ML HOME
-11.9% EV
-130
TOTAL OVER 6.5
-9.1% EV
-115
First 5 Innings & NRFI
BOS F5
1.9 runs
44.8% win
SEA F5
1.4 runs
32.4% win
F5 Total
3.3
NRFI
69.3%
YRFI
30.7%
Avg 1st Inn Runs
0.58
HR Spotlight
Avg HRs
1.7
Over 0.5 HR
81%
Over 1.5 HR
50%
No HR
19%
Willson Contreras BOS22.5%
ISO: 0.248 | Barrel: 15.3% | vs Logan Gilbert | Park: 0.89x
Jarren Duran BOS21.7%
ISO: 0.205 | Barrel: 8.8% | vs Logan Gilbert | Park: 0.89x Platoon: 1.12x
Dominic Canzone SEA13.6%
ISO: 0.157 | Barrel: 15.7% | vs Payton Tolle | Park: 0.89x
Pitcher Strikeout Projections
Payton Tolle
0.0 K projected
BOS | K/9: 0.0
Logan Gilbert
0.0 K projected
SEA | K/9: 0.0
Injury Report
BOS8 injured
Romy Gonzalez 1B60-DAY-IL
Isiah Kiner-Falefa 2B10-DAY-IL
Trevor Story SS60-DAY-IL
Patrick Sandoval SP60-DAY-IL
Roman Anthony LF10-DAY-IL
Garrett Crochet SP60-DAY-IL
+2 more
SEA8 injured
Luke Raley RFDAY-TO-DAY
Carlos Vargas RP60-DAY-IL
Will Wilson 3B60-DAY-IL
Randy Arozarena LF10-DAY-IL
Cooper Criswell RP15-DAY-IL
Brendan Donovan 3B10-DAY-IL
+2 more
AI Intelligence Analysis
LEAN +1RED ZONE45.4% WR (n=116)
Away underdog (BOS 51.3%) has +5.5% edge on ML (50.2% model prob vs 47.6% implied) with stellar F5 edge (+14.1%), NRFI edge (+3.6%), and under total edge (+0.2%) — multi-market confirmation suggests market slight undervaluing away team. SEA bullpen elite (3.37 ERA, 1.335 quality) but doesn't offset early-inning mismatch.
Key Factors
- F5 ML edge +14.1% (54.9% model prob vs market ~40%) — early-game mismatch suggests BOS control early
- NRFI edge +3.6% (66.4% model prob) — SEA bullpen strong but can't prevent early runs
- Both SPs quality (Gilbert 3.7 ERA vs Tolle 3.16 ERA) but Tolle slightly better; market underpricing away
- T-Mobile Park marine layer (5.2 mph in) slightly suppresses runs; cool 69.6F neutral
Risk Factors
- Away ML in RED zone (45.4% WR) — even with multi-market confirmation, zone history is caution signal
- Edge only +2.6% on ML — moderate, not strong
ML VALUEF5 VALUENRFI VALUEMULTI MARKETAWAY DOG CAUTION
Edge Analysis
Moneyline
BOS 51.3%
-15.6 pts
Run Line
-1.5
-15.6 pts
Total
6.5
+0.2 pts
How this prediction was generated: This page shows output from the Olympus Bets MLB Baseball Monte Carlo engine. Each game is simulated 10,000 times using real-time team data, injury reports, and current odds. Probabilities are calibrated using Bayesian methods and sized via the Kelly Criterion. Probabilities are calibrated using Bayesian methods and sized via the Kelly Criterion. Full methodology →