Who is Matt Shoemaker?

Make no mistake about it: Matt Shoemaker’s undaunted pursuit of the revival of his pitching career, after sustaining life threatening injuries the last time he toed the rubber against a major league hitter, is a master stroke of the human psyche. It’s an absolutely amazing narrative of perseverance in the face of improbable odds and represents one of the salient reasons so many of us are drawn to sports in the first place.

But for those same reasons, Shoemaker may find the narrative to be, in a way, inescapable. It may be some time before he’s able to pitch in a game without a commentator or interviewer referencing the line drive off Kyle Seager’s bat that shattered his skull. And while I don’t know Matt Shoemaker, I imagine that he hopes that time comes sooner than later. Because at the end of the day, Shoemaker, while he’s likely very grateful for his recovery, just wants to pitch — and ultimately, wants to pitch well.

Beyond whatever hurdle he’ll have to clear mentally, there’s something else I want to delve into, something that Shoemaker can work on to enable success for himself in 2017. In order to do this, we’ll have to sift through his strong 2016 performance, which, as I’m sure you’re aware, can be credited to his willingness to throw his split-change over 40-percent of the time — establishing a new high-water mark for usage of such a pitch by a starting pitcher, ever.

With that in mind, if we break up his season into three somewhat arbitrary endpoints, there appears to be a perfectly logical explanation to the varied degrees of success he experienced, though it may not be so simple as that in the end.

A bullet point flowchart depicting the cursory glance, logical explanation of Shoemaker’s 2016 reads as follows:

• April 8 - May 11: Shoemaker, sporting the 8th worst FIP in baseball among starters with 20 IP (slightly worse even, than Mike Pelfrey’s), is in jeopardy of losing his rotation spot; an adjustment is required.
• May 16 - June 27: Shoemaker starts throwing his split-change over 40-percent of the time and accrues baseball’s 4th best FIP, residing just behind Clayton Kershaw on the leaderboard.
• July 3 - September 4: The league adjusts to Shoemaker’s new repertoire and his performance settles in at what can only be described as a very Matt Shoemaker performance.

I’m going to go ahead and assume we’re in agreement that Shoemaker’s level of success over the first nine starts in which he incorporated the increased use of his split-change was unsustainable. But the regression he experienced in his final twelve starts cannot be entirely explained by the adjustment the league made against that pitch. In the latter third of the season, hitters started lifting the split-change more often, thereby increasing their ISO against it.

Nonetheless, from the start of the year through the end, his split-change remained a dominant pitch. So where do we look?

Well, we really start to get a whiff of something when we observe his pitch usage patterns.

Brooks Baseball

You see it, I see it, let’s talk about it. The nosedive trajectory of his slider usage represents a fall off from a robust 21.88-percent in April, all the way down to 4.97 in August and September combined — a puzzling development when you consider that, on the whole, Shoemaker’s slider was a plus pitch in 2016, inducing whiffs at 17.5-percent clip while suppressing batted ball authority to the tune of a cool 86.6 mph.

As potent as his fastball/split-change approach proved to be, it doesn’t appear Shoemaker was attempting to simplify his repertoire; rather, as the year went on, the dwindling results produced by his slider dictated its usage. As the graph below shows, the slider was inducing progressively fewer whiffs as the year went on.

Brooks Baseball

Here’s where things start to become pretty granular.

The decline in the efficacy of his slider is a byproduct of how a) its movement changed over the course of the year, and b) how its movement interacted with the movements of his split-change and fastballs. To show you what I mean, here is how the movement of his slider changed over the course of the year.

And here is how the movement of his slider interacted with the movement of his other pitches.

At the risk of inundating you with tables and graphs, here is a scatter plot from Brooks Baseball charting the movement of Shoemaker’s pitches. The most extreme left red dot represents the movement of Shoemaker’s slider at the beginning of the year, while the most southern red point is the slider at the end of the year.

Brooks Baseball

Summed up, Shoemaker’s slider was deteriorating into a less distinctive pitch in the context of the rest of his arsenal. But why did this happen?

Well, there are numerous reasons to speculate on as to what caused this, but my working theory is that it’s not impossible that it was an unintended consequence of throwing more split-changes, which may have affected how Shoemaker’s slider came out of his hand. You see, his slider was losing useful spin.

If you find your attention adrift at the mention of “useful spin”, hear me out — I intend to make this as undemanding as I can.

You can read to your heart’s content about spin rates and useful spin, but for this article I will cherry pick pertinent information from a seminal piece on spin axis by physics professor, Alan M. Nathan, who notes that the Magnus force, which is (from Wikipedia) “the commonly observed effect in which a spinning ball curves away from its principal flight path”, is only sensitive to the transverse spin, or spin axis, which travels perpendicular to the velocity of the ball.

Nathan goes on to design an elementary method to understand exactly what he means. Plucked directly from his article:

“The direction of the break can be determined from the tool by making a fist with your right hand placing it near the center of the circle. Orient your hand so that your thumb points to the red dot. Then your fingers will point in the direction of the break, as observed by the catcher.”

Determining the 3D Spin Axis from TrackMan Data - Alan M. Nathan

If you’re so inclined you can do this exercise using Shoemaker’s slider’s shifting spin axes from 2016 (recall from the table above that it changed from 141.85 to 174.31). Combine this knowledge with the fact that his slider’s spin rate jumped from 1922 to 2009 and you’ll fully understand why Shoemaker’s slider went from this:

To this:

Even if this diagnosis is right, the fix is likely simple only in theory. Since the release point on his slider was consistent throughout the year, a manipulation of the position of his hand, wrist, or grip could all potentially aid in returning Shoemaker’s slider to it’s superior form. Still, that’s easier said than done, especially while Shoemaker tries to maintain the rest of his repertoire.

The Angels’ (ace?) righty has already advanced through two crucial checkpoints laid out in his rehab this spring — throwing live batting practice and, finally, pitching in his first game since that fateful second inning last September. And that must feel good. But if he can harness the spin on his slider, he’ll be equipped with four quality pitches to attack opponents with, and could well surpass the high expectations of performance already associated with “Matt Shoemaker.”

And that would feel better.

Gary Coronado/Los Angeles Times

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Mark Davidson is a featured writer at Beyond the Box Score. You can follow him and send him bat flip gifs at @NtflxnRichHill