James Paxton and the Fastball
James Paxton, despite some inconsistency during his first season in pinstripes, is a pretty excellent pitcher by any standard. While he was not an ace in 2019, Paxton still managed to pitch 150+ innings with a 3.82 ERA in a season that saw offenses surge to levels not seen since the steroid era. Sure, Paxton struggled in the first inning of starts and he continually tweaked his pitch mix throughout the season, but Paxton’s performance was well above league average in the aggregate. While the book is hardly shut, the Yankees clearly won year one of the trade that brought James Paxton to the Bronx.
Despite his relative success, Paxton still has plenty of room for improvement as he heads into his final year of team control. Paxton’s WHIP was 1.28 in 2019, and while that’s not a bad number for a starter, it’s not much better than average. Digging even a little deeper, and it is immediately apparent that Paxton was more hittable than traditional statistics would lead one to believe. According to Statcast, Paxton ranked in just the 34th percentile in both Hard Hit Rate and Exit Velocity allowed. Hitters also barreled balls against Paxton at an above-average rate, as Paxton ranked in just the 42nd percentile in that statistic. Pitchers constantly look to improve their performance, but Paxton has now publicly admitted to altering a major element of his arsenal: his fastball.
Paxton told George King III of the New York Post that he has intentionally changed his grip on his four-seam fastball in an effort to generate a higher spin rate. By decreasing the pressure of the thumb on the ball, Paxton has verified that he can generate more backspin on his fastball.
Initially, this sounds like a positive development. Higher spin rate on the fastball has been proven to correlate with higher swing and miss rates when used at the top of the strike zone. According to Statcast, the spin rate on Paxton’s fastball ranks in just the 39th percentile as compared to the rest of the game. If Paxton is generating a higher spin rate, surely this is a good thing.
However, there is more here than meets the eye. For one, Paxton already generates more whiffs than most pitchers in baseball, ranking in the 81st percentile. Additionally, Paxton’s fastball already generated a solid whiff rate of 24.6%.
Additionally, on an anecdotal note, the fastball is one of the most basic and natural grips used by any pitcher. Changing the grip of a pitcher’s standard fastball is not terribly common, beyond changing the primary fastball from a four-seamer to a two-seamer/sinker, or vice versa. Changing that grip can have all kinds of unintended consequences. Paxton is not a pitcher that is known for having excellent command, but changing way in which he holds and releases the fastball could conceivably have a negative impact on Paxton’s ability to control and command the pitch under pressure.
On the flip side, while Paxton’s whiff rate was already well above-average, Paxton’s fastball was hit more than one would expect given his above-average velocity. Paxton allowed a .357 wOBA and 88.1 MPH Exit Velocity on the pitch, marks that indicate that Paxton’s fastball really was not a terribly strong offering. Additionally, Paxton’s measured spin rate on the pitch was just 2263 RPM, fairly low for a fastball. Digging deeper into the whiffs that Paxton did generate with his fastball, it is telling that the majority of his whiffs were on fastballs up in the zone. Additional spin could be the difference maker on pitches up in the zone, giving Paxton a more dangerous weapon to pair with his curveball down in the zone.
Obviously, we don’t have all of the answers yet. It is easy to see why additional spin on the fastball could be a great thing for James Paxton, but not if it comes at the expense of control and command. Time will tell the tale, but I will be watching closely to see what Paxton’s fastball looks like whenever baseball returns.