On April 1st of 2016, Jake Arrieta of the Chicago Cubs became just the 35th pitcher in big league history to throw at least two no-hitters with his 16-0 shutout of the Cincinnati Reds. After winning the NL Cy Young the previous season, he made the lone All-Star Game of his career in 2016, and finished ninth in Cy Young voting for the second time. Following a steady downward trend over the following four seasons, he too is coming off the worst season of his career.
According to Baseball Savant’s percentile rankings, he didn’t do anything better than most major league pitchers other than prevent walks. However, that’s only particularly helpful if, when you do throw strikes, they’re not meatballs served on a silver platter for batters to demolish.
After 2016, he lost around three mph on average, and therefore the ability to ideally mix in a high, straight heater in addition to feeding hitters a steady diet of sinkers at the bottom of the zone. He no longer possesses the power sinker that would occasionally approach triple-digits, and his fastball has averaged around 92 mph since 2017, when he gave up the four-seamer for good and started throwing exclusively sinkers.
In reality, Arrieta’s never really owned any particular portion of the zone, but has mostly just thrown his fastball for indiscriminate strikes, hoping his speed and movement will make up for any lack of precision. With a slightly shrunken, dulled arsenal, Arrieta immediately regressed from awesome to okay, and has continued his slide after each successive season into the present.
In 2020, Arrieta’s sinker was hit harder than ever before, to the tune of a semi-outrageous .402 batting average, .634 slugging, and .462 wOBA. The small sample size of the 2020 season could have something to do with the those awful numbers, but every one of Arrieta’s marks in those categories has been worse than the season prior since 2015.
Arrieta’s sinker location, velocity, and pitch mix, and even its movement have all remained relatively stable and solid, so it’s hard to locate a specific cause for Arrieta’s increasing woes. His fastball spin rate has diminished drastically, but curiously, it’s done so even without a dip in his velocity. Pitchers occasionally gain spin rate by improving their mechanics, or lose spin rate as they age or get injured, but those losses almost always correspond to comparable moves in pitch velocity.
Over the most recent season, when Arrieta saw his biggest drop in fastball spin rate, his average movement on the pitch actually increased, from almost an inch, to nearly two. While that’s not a ton of movement, it’s enough spin to turn an extremely heavy sinker with a sneaky lack of sink into a more normal one that fades arm-side and down. Counterintuitively, as it’s gained more downward tilt, Arrieta’s pitch hasn’t necessarily been hit skyward any more often, but it’s become a more predictable pitch batters are used to seeing. While he’s still squarely a groundball pitcher, he gave up the highest line drive and barrel rates of his career in 2020.
It’s difficult to know exactly why Arrieta’s sinker looks more like, well, a sinker than ever, but it’s possible that fact, in addition to batters’ acclimation to him over time, has contributed to his dwindling success. It’s possible, Arietta’s falling towards the first-base side of the mound on his finish, contributing to the greater tailing action on his pitches, but with such slim margins of change, it’s impossible to say for sure.
If he can’t recapture his sinker of yore, Arrieta should at least consider leaning a bit more heavily on his legitimately dangerous changeup. Compared to his measly sinker, Arrieta’s two offspeed offerings were nearly twice as effective in every major offensive rate statistic. His tight slider acts more like a cutter, effectively contrasting the sinker’s fading action. His nearly 90 mph changeup completely falls off the table, with eight inches more break than the average changeup around the same speed. Each pitch, in its own right, is pretty filthy, and Arrieta would be best served by a bit more craft, instead of approaching opponents with the mindset of a 27-year-old flamethrower, and the arm of a a senior whose stovetop’s stuck on low.
If the Yankees feel confident in Arrieta’s ability to develop his offspeed pitches into options that can be thrown as often as his sinker, they could seriously help the 34-year-old redefine the latter portion of his career. Ideally on the Yankees, with the aforementioned changes, Arrieta could be an excellent middle of the rotation starter, capable of eating up a large number of innings in the regular season, and possessing the fortitude to pitch in the playoffs. If Jake Arrieta’s addicted to the idea of himself as a sinker-baller, the Yankees ought to turn their attention elsewhere.