We’re familiar with the Yankees and their current injury peril (or lack thereof) at the moment. Despite losing nearly their entire starting lineup—Aaron Judge, Giancarlo Stanton, Didi Gregorius, Aaron Hicks, and Miguel Andujar—as well as their ace starter in Luis Severino, it should have foreboded an awful April. Instead, the Bombers have won 17 of their first 28; only three teams right now have more wins, and only three have more home runs.

This was partially due to how well the B-squad has performed, such as Clint Frazier (before getting injured), DJ LeMahieu (before also getting injured), and Luke Voit. Yet the pitching has really been what has kept them afloat. The Yankees have performed very well in the top pitching categories:

fWAR: 3rd

K/9+: T-4th

ERA-: 8th

FIP-: 6th

That seems very improbable to accomplish without the help of Severino, and yet they have done it by adding another top-30 starting pitcher in James Paxton. Acquired in a deal that sent both Erik Swanson and Justus Sheffield (now both on the 25-man) to Seattle, this was a win-now move that was meant to buttress the advantage they had built with Severino and Masahiro Tanaka at the top.

Instead it has been a performance stopgap, and it has been wholly necessary. If you were to peruse the FanGraphs leaderboards, you can see that Paxton ranks second overall in pitcher fWAR, and second in K/9+ only to former Yankees (and possibly future) target Gerrit Cole.

How has he done that? Strikeouts, of course. The Yankees as a team have stressed slider-slider-slider. That has worked for the most part; their bullpen has been stellar and their K-rate has climbed over the years, but the results could be inconsistent at times. Sonny Gray, for example, did not take to this approach and has since returned to the four-seamer as his primary pitch.

With Paxton, this has not been the case. Instead of focusing on a breaking pitch, they have essentially leaned into his abilities as a lefty who throws a really, really hard fastball. Sometimes that’s most of what you need. But, if you look at his pitch repertoire, you’ll see a small but noticeable change:

As to be expected, he is still a fastball-first pitcher. When you throw as hard as he does, you ought to. Yet you can see that small uptick in cutter usage, and it makes a lot of sense. Instead of throwing a slider more often, which could make sense as one’s velocity declines, the tunneling of a 98 mph fastball against an 87 mph cutter makes it even more difficult to hit considering the pitch’s plane. And by leaning into the fastball, which now makes up over 85% of his pitches, his whiff rate on breaking stuff has only increased by contrast.

I mean, just look at one fastball against the Giants last week...

..followed by an example cutter...

...and then, look at what a curve looks like in comparison:

On that curve in particular, look at how foolish Kevin Pillar looks there. The reason for this is not only velocity differential—which is something like 13-15 mph from a four-seamer to there—but also a spin differential. While Paxton’s fastball spin is pretty normal at the 57th percentile (2283 rpm), his curveball, which is actually a knuckle curve, is at a mere 1949 rpm, just the 5th (!) percentile overall.

It’s crazy to even opine this, but Paxton could very well get even better. The fastball is dynamite, as has been known for a while now, but the cutter and curve figure to be very useful weapons, especially that curve. You can see how he uses those pitches in various counts...

..and it’s easy to see where he could improve. When the day comes when his fastball is lessened, using that curve in more counts, even when you’re behind, could really counter a hitter’s balance more than the four-seam/cutter already does. One day I expect Paxton to morph into a cutter/curve pitcher, but that’s for a half-decade from now.

As of today, in 2019, Paxton could very well be one of the best pitchers in baseball, and there’s evidence to show he’s improving on that. With the introduction of the cutter as his secondary pitch and continuing to establish the curve as an effective slow-spin weapon, the Yankees have found a more-than-adequate Severino replacement when he’s done. And when he does eventually return, that’s a one-two combination that would be hard to combat in a short playoff series.