Jake Arrieta has naturally evolved since his dominant 2015 campaign. Some might suggest the evolution to becoming a sinker-heavy starter was necessary because his stuff hasn’t been as jaw-dropping.
Today, the former Cy Young Award winner’s method of getting batters out is to throw sinkers inside to righties and show just enough curves, changes, and sliders. While his sinker usage is so high that it might not be sustainable going forward, Arrieta is nevertheless displaying much better accuracy, maybe even better than his overwhelming 2015 season.
Saying that we can reduce Arrieta’s changes with just three pictures is a little tongue-in-cheek, but I think the following three images do paint a picture of his evolution with broad strokes. As seen below in heat maps from 2015 to now, the Cubs starter has increasingly darted sinkers to a narrow region of the strike zone, suggesting either he’s becoming more accurate or just reliant on the left portion of the zone.
In 2015, Arrieta left lots of sinkers over the middle of the plate, but he got away with it because of his unique stuff. Then in 2016, his command waned and he left a noticeable number of sinkers belt high in the middle. This year, Arrieta has not only thrown more sinkers to the left side of the zone, but he’s doing so with more specificity. Not many pitches are being grooved nowadays.
What’s clear to me is that Arrieta is exercising better control this year despite not having that same 95 mph velocity. Whether you feel more comfortable with the 2016 or 2017 version of Arrieta is up to you. Personally, I feel better about this year’s version, as the upcoming free agent might be displaying the best command as his tenure as a Cub.