jake arrietaLast night, Jake Arrieta went seven scoreless innings, allowing just two hits and one walk, and striking out nine. Just how good is a start like that? Well, Arrieta’s win probability added in the game – 0.43 – made his start the pitching equivalent of a batter going three for four with two homers (roughly speaking).

Other bits on Arrieta’s big night …

  • Coming into the game, Arrieta’s ERA was already a scant 2.50. After the game, it dropped all the way to 2.09.
  • Similarly, Arrieta’s FIP and xFIP dropped from 2.58/3.16 to 2.32/2.89. If he had enough innings to qualify, those would be the third best and 10th best marks, respectively, in all of baseball.
  • Arrieta’s strikeout rate climbed from 22.6% to 24.6%, and his walk rate fell from 8.4% to 7.8%.
  • Arrieta got an unbelievable 13 swinging strikes last night, according to Brooks Baseball. Think about how many whiffs that is. Just crazy.
  • When he wasn’t notching strikeouts against the Phillies, Arrieta was once again a groundball stud: of his non-strikeout outs, seven were groundouts, one was a sac bunt, and four were fly/pop/line outs.
  • No surprise, then, that Arrieta’s excellent groundball rate more or less held steady after the start (from 52.0% to 52.1%).
  • And now my favorite: Arrieta has already accumulated 1.3 WAR, according to FanGraphs, in just 8 starts and 43 innings. If he threw 215 innings this year – that won’t happen, but just stick with me for fun purposes – that 1.3 WAR extrapolates to 6.5 over the course of a season. 6.5 WAR!