What might be behind the Yankees’ new fascination with sinkers?

When Statcast debuted its new tracking system, Hawk-Eye, to the public, there were fun tidbits about the potential of bat path and limb-tracking data. This article from Joe Lemire of Sport Techie gives a thorough summary of what the expectations were for Hawk-Eye and what was new compared to the previous tracking system, Trackman.

Here is the most relevant part of the story, as far as this article is concerned:

“We’ll be looking at arm angles, we’ll be looking at stride lengths. And we’ll also be looking at bats and tracking the bat.”

With bat-path data, there are two benefits that come to mind. First, pitchers can more thoroughly understand the capabilities of their opponents. On the flip side, hitters can more easily explore their in-game swings and what their process looks like for attacking a pitch. Unless you have a bat sensor on in-game, there is no other way to get this data. Obviously, major leaguers don’t do this, making the information more important to teams. I’m going to focus more on the pitching side of things.

Our own Peter Brody recently discussed the uptick in sinker usage and how the Yankees are one of the teams leading the charge. Between acquiring some sinkerballers at the trade deadline and current Yankees adding the pitch to the repertoire, it’s become evident that something is up. As Peter pointed out, this could be because not all pitchers have the ideal arm slot for perfect four-seam backspin, or that the sinker is a useful tool if pitchers no longer have access to sticky stuff. Add the newly reliable bat-path data and more precise pitch-tracking tools and we have ourselves some valid explanations for the uptick in sinkers.

But how has intuition changed from years past? Is the sinker still not directly in the wheelhouse for hitters with highly positive attack angles like Gallo and Judge? Well, it depends. If a pitcher throws his sinker in a traditional way in the bottom third of the zone with some arm-side run, then yes, it is still perfectly in a home run hitter’s wheelhouse. However, if a sinkerballler can locate the pitch elsewhere while staying away from the bat path that a hitter typically takes to get to the ball, then the pitch has the potential to be effective. Depending on the spin direction and axis of a pitcher’s sinker, this can be a viable strategy.

There is a hole in the theory of the sinker moving in the perfect direction for an optimal bat path. That idea completely ignores factors like the horizontal approach angle of the pitch or the direction in which it is moving and spinning.

Picture Clay Holmes’ sinker:

It’s a side-spinning, high-velocity sinker that has elite deviation between spin-based and observed movement. In simpler terms, a hitter’s eyes are being deceived because there is a difference in which direction the ball is spinning and how it appears to the hitter.

Not only are the hitter’s eyes being deceived, but the odds are that their bat path is usually not in this pitch path either. This is not a traditional, downward-spinning sinker. Holmes throws his sinker faster than anybody with that much spin deviation — 95.7 mph on average with wonky-side spin that is difficult to pick up makes for an extremely unique pitch.

On pitch characteristics alone, it is elite. Pair that with the bat path of a righty who most likely is not covering a pitch spinning from the lefty batter’s box in a horizontal direction, and you have an extremely effective pitcher against right-handed hitters. Fellow PSA writer Andres Chavez pointed out that Holmes’ sinker is highly similar to that of Marcus Stroman’s. Not so coincidentally, Stroman is the only right-handed pitcher who gets more spin deviation on his sinker than Holmes, but Holmes’ velocity makes up for it.

Only with accurate bat-path data can we assert this theory with 100-percent confidence, but the logic is there. A same-handed hitter cannot simultaneously create an optimal path that covers a pitch across the opposite batter’s box. Joely Rodríguez’s sinker spin and movement reinforce this statement when we think of it in terms of left-on-left matchups.

Like Holmes, Rodríguez has elite deviation between spin-based movement and observed movement on his sinker, and he throws it harder than most lefty sinkerballers with that level of deviation. Both pitchers also have elite movement. From a usage standpoint, these pitchers are essentially the opposite-handed version of one another when it comes to their sinkers.

Rodríguez dominates lefties and can really take advantage of throwing to zones that are difficult for them to cover, as MVP frontrunner Shohei Ohtani can attest:

This take by Ohtani makes a lot of sense. His athleticism allows him to cover different zones and different speeds. In other words, he can create different swing paths. However, a pitch in this zone moving in the direction that it does is very difficult to cover if you’re not exactly looking for it, even if you are as elite as Ohtani.

It’s the same reason why Holmes’ backdoor sinker can be so effective. Elite hitters know themselves and take pitches that they cannot reach. These sinkers are tough pitches for same-handed hitters. Again, I cannot show you this for sure without showing you the exact path they take to pitches, but the reasoning tracks very well.

Don’t get me wrong, these sinkers can still get shelled if they are not located well. Obviously, Holmes and Rodriguez have not been elite up this point in their careers. But they have serious potential to be effective if they can use their secondaries well enough to keep hitters confused. They are both deceptive in terms of delivery and pitch movement.

It’s certainly exciting that the Yankees seem to be leading the charge in bringing sinkers back. It was always confusing that even when sinkers went out of style, specific pitchers still had considerable success with the pitch. Hawk-Eye has only helped teams, including the Yankees, take more reasonable risks with acquiring players. Whether it be with bat-path or pitch-tracking data, they have a plenty of information to execute new ideas.