San Francisco Giants vs Boston Red Sox: MLB Prediction, Pick & Odds — Aug 21, 2026

31-46

PregameFri, 7:10 PM EDT

BOS

31-44

Verdict

Pass · no edge tonight.

The model doesn't see daylight against the posted line on this game. We don't surface negative-EV picks; check the drill-down for sub-model context.

Why this matchup

1 signal · model + market

Park factor

104 total idx

Fenway Park run environment

Park factor boosts run scoring, so contact quality matters more tonight here.

Fenway Park · Boston, Massachusetts

Drill down

Sub-model tables · ensemble breakdown · last meeting · book shop · player props

Pregame · scouting report

The matchup, end-to-end.

Probable starters, projected lineups, head-to-head this season, our model edge against the market — every angle on one surface.

Away starter

TBD

Probable starter not yet announced. ESPN typically posts the card 12–24 hours before first pitch.

Home starter

TBD

Probable starter not yet announced. ESPN typically posts the card 12–24 hours before first pitch.

Vegas line

Lines post once a sportsbook releases them.

Model edge

Our model rates this game once both starters are confirmed.

Head to head

SeriesSeries starts 8/21

TypeRegular Season Series

Model ensemble · how the prediction is built

3 sub-models, blended.

Each sub-model uses a different rating substrate. Bayesian model averaging weights them by rolling Brier score so the ensemble inherits each model's strengths. Disagreement flags games where the sub-models don't see eye-to-eye — lower confidence, wider band.

49.5%

ensemble · SF favored

Elo Static
fallback · inputs missing
50.0%
P(BOS win)
33%
weight
Elo Pitching
fallback · inputs missing
50.0%
P(BOS win)
32%
weight
Bullpen Park
fallback · inputs missing
50.0%
P(BOS win)
34%
weight

Disagreement

0.00 pp

weighted σ across sub-models

Confidence

100% · high

maps from disagreement

Substrate count

0 / 3 active

ones with full inputs tonight

Weights recalibrated nightly on a 90-day rolling window with strict point-in-time correctness — no model gets credit for a game it hasn't seen. Headline % is Platt-scaled per league; sub-model rows show raw BMA inputs.

Player projections

BOS vs SF.

Per-player stat projections built from a recency-weighted blend of the last ten games, season average, and matchup context. Confidence reflects sample size and stability — the top of each list is who to watch.

130

projections · 83 high confidence

Strikeouts

Landen RouppSF
5.9± 1.8medium
Ranger SuarezBOS
5.7± 3.6low
Logan WebbSF
5.5± 1.5low

Hits

Casey SchmittSF
1.4± 1.0high
Luis ArraezSF
1.3± 0.9high
Jung Hoo LeeSF
1.2± 1.0high

Total bases

Bryce EldridgeSF
2.2± 2.3high
Ceddanne RafaelaBOS
2.1± 2.4high
Casey SchmittSF
2.1± 2.3high

RBIs

Ceddanne RafaelaBOS
0.7± 1.3high
Bryce EldridgeSF
0.7± 1.2high
Marcelo MayerBOS
0.6± 1.0high

Earned runs

Adrian HouserSF
2.9± 2.7low
Landen RouppSF
2.8± 2.5medium
Trevor McDonaldSF
2.8± 2.6low

Projections recompute every 30 minutes · prop lines plug in once sportsbook ingest lands

Matchup · 2026

Team rate stats vs league

MLB Stats API

league avg

BOS

.728

OPS

◀

.719

.692

.309

OBP

.319

.311

4.12

Runs / G

◀

4.50

3.92

4.46

Team ERA

4.19

▶

3.85

1.39

WHIP

1.31

▶

1.26

8.1

K / 9

8.5

▶

8.5

Data via ESPN · MLB Stats API · Baseball Savant

San Francisco Giants at Boston Red Sox

The matchup, end-to-end.

3 sub-models, blended.

BOS vs SF.

Team rate stats vs league

3 sub-models, blended.