Bombsight scores every HR pick on six axes from 0–10. The composite is a weighted average rounded to one decimal. This page explains each axis — what it measures, how it scores, what "good" looks like, and shows an example value.
How HR-prone the opposing pitcher is based on his season-long rates.
HR/9 carries the most weight (45%) — league average is ~1.1. Barrel rate allowed (30%) and hard-contact rate (25%) add secondary signal. A wide LHB/RHB OPS split adds a small penalty (−0.5) because one-sided matchup advantage is exploitable. A leaky bullpen (ERA > 5.0) adds another −0.5 since inherited runners inflate HR risk.
≥ 7.0 — typically a pitcher with 1.6+ HR/9 or barrel rate allowed ≥ 10%. Elite vulnerability (≥ 9.0) is rare; a score near 5 is league-average pitching.
The batter's intrinsic home run ceiling for this specific matchup side.
Exit velocity average and barrel rate each carry 30%; pull rate (20%) and hard-contact consistency (20%) round out the score. A platoon advantage (L vs. RHP or R vs. LHP with high opponent OPS splits) adds +0.4. Strikeout rate above 25% subtracts 0.4; above 30% subtracts 0.8 — high-K hitters are inconsistent power threats.
≥ 7.5 — a batter with 95+ avg EV, 10%+ barrel rate, 48%+ pull rate, and clean platoon alignment. A score of 6.0 still has upside; below 4.0 is an unlikely HR candidate.
How hard the batter has been hitting the ball in the last 7 days — recent form, not season form.
Two inputs, equally weighted: average exit velocity across the last 7 batted balls (benchmark mid: 98 mph), and the fraction of those balls at 95 mph or higher (benchmark mid: 40%). Missing data defaults to 5.0. A batter on a hot stretch can lift this axis even if season numbers are modest.
≥ 7.0 — typically 6 of 7 recent batted balls at or above 95 mph with an avg EV near 100 mph. A cold stretch (mostly soft contact) typically produces 3.0–4.5.
Whether the ballpark and game-day conditions amplify or suppress home run carry.
Starts at 5.0. Elevation above 1,000 ft adds up to +0.75 (Coors effect). Wind blowing out at 10 mph adds ~1.5 (capped at +2.0); wind blowing in at 10 mph subtracts 1.0; crosswinds at 10 mph subtract 0.5. Temperature above 80°F adds +0.5; below 50°F subtracts 0.5. Park factor above 1.0 adds a linear bonus. Domes subtract 0.5 for weather irrelevance. Result is capped 1–8.
≥ 6.5 — tailwind with warm temps at an above-average HR park. A score of 5.0 is neutral. Below 4.0 means suppressing conditions (strong headwind or cold park).
DFS-specific edge: how much GPP value a low-ownership HR pick generates.
Ownership score: contrarian picks (< 5% owned) score highest; public chalk (> 20%) scores lower (inverted scale). Leverage index: high-leverage game situations (close late game) score higher. Salary efficiency: cheap options (< $4,000) add +1.5; expensive plays (> $7,000) subtract 0.5. Weights: ownership 40%, leverage 40%, salary 20%.
Context-dependent. For HR plays, 6.0–7.5 is a sweet spot: low-ish ownership in a high-leverage game. Very high scores (≥ 8.5) mean extreme contrarian exposure — high upside but also volatile.
How the pitcher has actually been performing in his last 3 starts — recent momentum, not season stats.
Averages ERA across the last 3 starts. ERA ≤ 2.5 scores 8–10 (dominant, suppressing HR); ERA ≥ 5.5 scores 1–3 (leaky, HR-favorable). Between 2.5–5.5 the score interpolates linearly. A hard-contact rate well above 35% baseline in those starts adds a further −1.0 to −1.5 penalty. Fewer than 3 starts defaults to 5.0.
≤ 3.5 is GOOD FOR THE BETTOR — it means the pitcher has been getting shelled lately. A score of 8+ signals the pitcher is dominant and HR equity drops significantly; this triggers a red flag on the pick.
Composite = weighted sum of all six axes, rounded to one decimal. Axis 6 (Pitcher Recent Form) is scored so that a LOW value is good for a bettor — a dominant pitcher hurts HR equity.