1st Inning

Team-level Over/Under runs scored in the 1st inning. Model combines each starter's FIP, the opposing lineup's OPS vs that handedness, and a Negative Binomial fit to single-inning MLB run scoring (Walk Like A Sabermetrician, 2012). Sportsbook market totals_1st_1_innings; line 0.5 is the classic "Run In First Inning" prop.