We’ve made what are likely (hopefully) our final methodological tweaks of the 2014 pre-season.
First, we started accounting for pitcher defense (including how pitchers affect the running game) which helps Clayton Kershaw and Mark Buehrle among others. We also tweaked how we project HR’s allowed for pitchers and shifted how we build our pitcher priors (regression means) so that they line up with today’s offensive levels.
We are now projecting a league ERA of 3.95 (the league had a collective ERA of 3.87 last year and 4.01 the year before) and a 3.95 FIP based on 7.56 K/9 (actuals of 7.57 and 7.56 the last two years), 3.01 BB/9 (3.02 and 3.05) and 1.02 HR/9 (0.96 and 1.02). We’re not forcing our averages to match a specific expected league average but it’s certainly reassuring if we’re quite close to what you’d reasonably expect.
The starter who benefitted the most from our tweaks was Clayton Kershaw’s whose ERA fell from 3.11 to 2.93 — thanks mostly to our inclusion of pitcher defense and, to a lesser degree, from our new HR allowed formula (note that while Kershaw’s actual HR projection ticked up slightly his HR/9 relative to the league actually went down). Zach McAllister moves in the other direction, from 4.40 to 4.62. Aroldis Chapman is the winner among relievers falling from 2.11 to 1.93.