The Pirates have a slight edge because their offense is stronger overall. The Red Sox have the advantage in defense and how sustainable their pitching has been, which keeps the matchup close.
Why 53%?
8 of 15 categories could be scored from the data on file. The 7 unscored categories are listed openly rather than guessed at, and their weight is shared across the categories that could be measured.
Offense
The home club has a clear edge in offense (100 vs 105 wRC+).
- Team wRC+ (away) 100 MLB Stats API
- Team wRC+ (home) 105 MLB Stats API
- Team OPS (away) .717 MLB Stats API
- Team OPS (home) .734 MLB Stats API
- Runs per game (away) 4.27 MLB Stats API
- Runs per game (home) 4.73 MLB Stats API
- Hard-hit % (away) Unavailable MLB Stats API
- Hard-hit % (home) Unavailable MLB Stats API
Starting Pitcher
Neither club has a meaningful edge in starting pitching (3.91 vs 4.43 FIP).
- Starter FIP (away) 3.91 MLB Stats API
- Starter FIP (home) 4.43 MLB Stats API
- K-BB% (away) 12.4 MLB Stats API
- K-BB% (home) 15.1 MLB Stats API
- WHIP (away) 1.68 MLB Stats API
- WHIP (home) 1.14 MLB Stats API
- Opponent OPS (away) .815 MLB Stats API
- Opponent OPS (home) .643 MLB Stats API
Bullpen
Bullpen splits have not been imported for both clubs.
Lineup / Platoon
The home club has a clear edge in platoon matchups (.733 vs .749 OPS in their stronger split). Starter handedness and confirmed lineups are not wired up, so this is a club-level split rather than a true lineup-versus-starter read.
- OPS vs LHP (away) .733 MLB Stats API
- OPS vs RHP (away) .711 MLB Stats API
- OPS vs LHP (home) .703 MLB Stats API
- OPS vs RHP (home) .749 MLB Stats API
- Confirmed lineup Unavailable
- Platoon advantage count Unavailable
- WAR missing from lineup Unavailable
Pitch-Type Matchup
Pitch usage and hitter results by pitch type are not in the daily snapshot yet, so this category is not scored.
Defense
The away club has a strong edge in defense (.708 vs .706 defensive efficiency). DRS and UZR have no free public source and are left out rather than estimated.
- Defensive efficiency (away) .708 MLB Stats API
- Defensive efficiency (home) .706 MLB Stats API
- Outs Above Average (away) 20 MLB Stats API
- Outs Above Average (home) -16 MLB Stats API
- Defensive Runs Saved Unavailable
- UZR Unavailable
Baserunning
Needs full player-level import for both clubs; only teams with individual hitter snapshots roll up to a team baserunning total.
Recent Form
The home club has a clear edge in recent form (5-5 vs 6-4 over ten games). Ten games is a small sample, which is why this is weighted lightly.
- Last 10 (away) 5-5 MLB Stats API
- Last 10 (home) 6-4 MLB Stats API
- Last 5 run differential (away) Unavailable MLB Stats API
- Last 5 run differential (home) Unavailable MLB Stats API
- Streak (away) W2 MLB Stats API
- Streak (home) L1 MLB Stats API
Ballpark Fit
PNC Park suppresses home runs (93 home run factor). Neither club has a meaningful edge in how this park suits them (.150 vs .150 ISO).
- Run park factor 96 MLB park-factor baseline (multi-year estimate)
- Home run park factor 93 MLB park-factor baseline (multi-year estimate)
- Double park factor 102 MLB park-factor baseline (multi-year estimate)
- Team ISO (away) .150 MLB Stats API
- Team ISO (home) .150 MLB Stats API
Weather
No weather feed is wired up, so temperature, wind and carry are not scored.
Rest / Fatigue
Travel, days rest and schedule density are not tracked yet.
Injuries
There is no injured-list feed, so missing WAR is not scored.
Historical Calibration
Judged against how this season has actually gone, the rest of the model looks a little high on the home club, by about 4 points. That read is backtested over 52 completed games at 56% accuracy.
- Backtest sample size 52 games NumSOX backtest
- Backtest accuracy 55.8% NumSOX backtest
- Brier score 0.254 NumSOX backtest
- Calibration adjustment +4 pts to the Red Sox NumSOX backtest
Regression Risk
The home starter's ERA is running well under his FIP, which suggests he has been getting some help.
- Starter ERA (away) 5.07 MLB Stats API
- Starter FIP (away) 3.91 MLB Stats API
- Starter ERA (home) 3.49 MLB Stats API
- Starter FIP (home) 4.43 MLB Stats API
- Team BABIP (away) Unavailable MLB Stats API
- Team BABIP (home) Unavailable MLB Stats API
Live Game State
The game has not started, so score, inning and base state carry no weight yet.
Data Sources & Freshness
Each supporting statistic above carries its source and latest available update date. Missing feeds are marked unavailable and do not receive model weight.
Estimate generated Sep 26, 2026 4:38 PM.
This is a custom NumSOX estimate based on baseball statistics, not a betting line or a prediction of certainty.
- Defense (.708)
- Historical Calibration (+4 pts)
- Regression Risk (+1.16 ERA-FIP)
- Offense (100 wRC+)
- Lineup / Platoon (.733 OPS)
- Recent Form (5-5)
- Offense (105 wRC+)
- Lineup / Platoon (.749 OPS)
- Recent Form (6-4)
- Defense (.706)
- Historical Calibration (-4 pts)
- Regression Risk (-0.94 ERA-FIP)