Jake Arrieta’s Elevated Walk Rate
When looking at Jake Arrieta’s season thus far, it’s really hard to complain. His 1.74 ERA and 0.98 WHIP are virtually indistinguishable from his 2015 combo of 1.77/0.86. Expanding out further, the 28% K rate, 0.3 HR/9, .244 BABIP, and 57% GB rate look virtually identical to the 27%, 0.4, .246, and 56% marks from last year. There has been one stark difference, though. Arrieta’s walk rate has climbed from 6% to 9% this year. To put a finer point on it, he walked 48 batters in all of 2015; he has 40 already this year.
So what’s going on and should we worry at all?
First place I usually look with walk issue is first-pitch strike rate. Is Arrieta falling behind early and losing more hitters? The answer to that is a flat “no”. His 60% rate is the same as it was last year and if you move the decimal out, he’s actually a tiny tick better at 60.4% compared to 60.2%. From there I go to the chase rate. Are batters spitting on more pitches outside of the zone? That is definitely the case so far this year. His O-Swing rate was 34% last year, good for 11th in baseball. He’s down to 29% this year, just 49th among the 96 qualified starters.