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FIP (Fielding Independent Pitching) is a sabermetric stat that strips defense and luck out of pitcher evaluation. It's more predictive of next-start ERA than raw ERA. Here's how it works and why it matters for betting.
FIP estimates a pitcher's run prevention based ONLY on outcomes the pitcher fully controls: strikeouts, walks, hit-by-pitches, and home runs. Defense + ball-in-play luck are stripped out. The formula:
FIP = ((13 × HR) + (3 × (BB + HBP)) - (2 × K)) / IP + FIP-constant
The FIP-constant (typically ~3.10) calibrates FIP to the same scale as ERA so the two are directly comparable.
ERA includes outcomes the pitcher doesn't fully control, defensive plays, BABIP variance, sequencing luck. A pitcher with a 4.50 ERA but a 3.00 FIP has been UNLUCKY (defense fails them, hits cluster) and is likely to regress positively. The opposite, 3.50 ERA, 4.50 FIP: is a pitcher who got LUCKY and will regress negatively. FIP is much more predictive of next-start ERA than past ERA.
100 = league average, 90 = 10% better than league. Removes both park and league effects, directly comparable across pitchers.Our model uses each starter's xFIP when MLB's Stats API has it (almost every game), falling back to Statcast xERA and then to a FIP (or park-adjusted fipMinus) and ERA blend. The SP run-margin term blends 85% of that pitcher-rate gap with 15% of the raw ERA gap, at 0.55 R per 1.0 run of gap (each starting pitcher throws ~5.5 IP, so 1 ERA × 5.5/9 ≈ 0.61 R). That SP term carries a 0.45 weight in the game margin against 0.55 for team run differential, and the team term is usually the larger of the two, so starter quality is a major driver but not the biggest.
When two pitchers' FIP differ by 0.5+ runs, the better one's team becomes a meaningful favorite even if their season ERA is similar.
Theory is one thing, using the concept on tonight's slate is the value. These hubs are the practical application: