NRFI / YRFI — First Inning Deep-Dive
NRFI (No Runs First Inning) is one of the most efficient prop markets — sharp price tightening means edges are small but consistent. The model combines starter ERA + park factor + lineup quality + bullpen warmup pattern to produce a per-game fair price.
--Games Scored
--YRFI Leans
--NRFI Leans
--League NRFI Baseline
--Top Edge
--Last Refresh
📊 Per-Game First-Inning Model
MatchupTimePitchersP(NRFI)P(YRFI)Fair YRFIFair NRFIVerdict
Loading per-game first-inning projections…
🧮 Model Inputs Explained
For each game's first inning, the model computes:
- P(scoreless top half) from the away pitcher's ERA blended with FIP, opponent lineup wOBA, and park factor. Using a Poisson-like inning-run distribution scaled by per-pitcher 1st-inning rate.
- P(scoreless bottom half) from the home pitcher's same blend.
- P(NRFI) = P(top scoreless) × P(bot scoreless) — independence assumption (reasonable for first inning since there's no momentum carry-over yet).
- Fair price from P → American odds, no vig added.
Lean YRFI when fair YRFI is >5% cheaper than market YRFI; lean NRFI similarly. Below that, skip (NRFI markets are tight, so edges <5% don't survive the vig).
📒 First-Inning Trends (reference)historical league baselines
Historical reference patterns from open MLB literature:
- League-wide NRFI rate hovers ~58% — books open the line near here.
- Aces on the mound (xFIP < 3.30) push NRFI to ~67%.
- Coors Field opens YRFI ~74% — historical altitude bias.
- 1pm Wrigley wind-out: YRFI bias ~70%.
- Bullpen game (no traditional SP for either side): YRFI bias ~67%.