Evolution, Cortisone, and Aaron Judge’s Shoulder

Aaron Judge’s season thus far resembles a graph many of you embrace as mathematically inclined baseball nuts, the rest running away, scorning the advance of statistics in this great game.

Our visual model is the cosine wave. Starting in the positives from square one, it dips below zero into the abyss, only to remerge and reach the same peak it originated at 360 degrees ago. Judge started on cloud nine, fell to cloud negative nine, and heading into the final weekend of 2017’s season, finds himself back where he started.

Narratives surrounding Judge’s slump, for the most part, remain mundane. Find any rolling game log of Judge’s stats and you will observe a gradual peak and subsequent decline for stats like strikeout rate, swing-and-miss rate, with the inverse true for more advanced metrics like Wins Above Replacement Player (WARP) and True Average Value (TAv). Industry minds have punted reasoning for Judge’s mid-season valley to an inevitable decline given how impressive the two tails of Judge’s season have been.

But a black hole occupies the space between. So what happened? The story begins with a decision – or lack thereof.

Joe Girardi & Co. – as reported by the Daily, and New York Post – considered a cortisone shot as an option for the ailing Judge, and for good reason.

“Cortisone shots are pretty amazing – they’ll take an incredibly painful area and reduce it to pain-free. The first cortisone shot I got felt literally like magic – my elbow pain was an 8/10, and as the needle entered, it was immediately down to a 1/10.” Dan Blewett, a former pitcher for the Atlantic League’s Long Island Ducks and current owner of a baseball academy in Normal, Illinois, admitted to me. Blewett had surgery twice to repair a torn Ulnar Collateral Ligament in his throwing arm, becoming an unfortunate expert on nagging injuries.

“Every team is different as far as the treatments they offer their players, but in crucial times – such as approaching the playoffs – they’ll often do what is necessary to keep a player on the field, as long as it doesn’t jeopardize their overall health.”

Judge’s shoulder remained tattered, mired in a grotesque slump. Shortly after, the public received insight that Judge would rest for multiple days, starting on Monday, August 28. He returned to the Yankees’ lineup as a pinch-hitter during the first half of an August 30 doubleheader, proceeding to to start the nightcap. That same day, reports – like three I linked above – started to emerge. To my knowledge, what doesn’t exist is confirmation that two days of inactivity completely healed his nagging shoulder; a common citation for his midseason void of production.

Travis Swachik, author of industry-leading book Big Data Baseball, does a fantastic job pointing out what changed during this downturn in Judge’s season. More fastballs, higher in the zone, more spin on said pitches, with a developing tendency to pitch Judge off the plate. This is a common adjustment pitchers make against hitters who graduate from “just another guy” to one of the game’s greats. With players of Judge’s size, high-and-tight usually prevents extension of a hitter’s arms and ability to drive the ball. Matt Olson, the Oakland Athletics’ first baseman, is another player with similar deficiencies that I’ve pointed out in the past.

While Judge routinely appears atop hard-hit metric leaderboards, the 25-year-old achieves even more immortality from the size of his strike zone. Mark Simon, an analyst for ESPN, notes not only how large Judge’s zone is, but how umpire tendency towards calling his zone have changed as calendars flip towards 2018. Judge went from seeing more called low strikes to called high strikes after the first two months of the season.

Evolving pitcher approach coupled with umpire adjustment did not provide any bridges for Judge to cross back to relevance. While there is rarely one reason for a hitter’s slump, singling out these changes adds context to Judge’s improvements after his two-day break.

From July 1 through August 27, Judge barreled eight of the 360 four-seam fastballs he saw in 200-plus plate appearances (under three percent). A “barreled” ball is a classification of batted balls that fall in the most beneficial windows of launch angle and exit velocity (Tom Tango is the visionary on this topic). Since Judge’s two-day break – August 28 and 29 – Judge has barreled 16 fastballs in just over 100 plate appearances; nearly half the amount of plate appearances and double the production.

To capture the entirety of Judge’s slump, we can move our July 1 parameter back two months. From May 1 through August 27 – nearly 500 plate appearances – Judge barreled 15 four-seam fastballs.

Nearly five times the amount of plate appearances as his post-break window, and nearly the same level of success. After that break, Judge became a menace against four-seamers.

However, it’s where these barreled fastball were struck that enlightens fans.

The flat, dark-brown line in the gif above are Judge’s 15 barreled fastballs from our large sample of games stretching from May 1 to August 27. This flatter picture morphs to show Judge’s torrid stretch of games in 2017’s final weeks since those two days off.  These barreled fastballs are noticeably higher in the zone compared to our prior period, and rest in the same part of Judge’s zone where pitchers and umpires seemed to collude against the righty earlier in the season.

Judge evolved.

But why are barreled fastballs an indicator of this evolution? For one, if you are barreling a ball its exit velocity exceeds 98 mph, about eight miles per hour above average. To generate that kind of kick off your bat, you need bat speed, especially given knowledge that bat speed provides six times more of an impact on exit velocity than pitch speed. More exit velocity is rarely a detriment for hitters.

If Judge’s bat speed increased during the period subsequent to his two-day break – where he began to barrel more fastballs up in the zone – we are observing a potential reason for his resurgence.

This change in Judge’s results could be the product of mechanical tweaks independent of his health, or Judge could have put his shoulder and other bodily issues behind him during his break in pursuit of productivity.

The essence of hitter analysis is how often changes this material lack one, all-encompassing reason, but that uncertainty provides ample room for theories to emerge.

“The front shoulder is a crucial player in a hitter’s swing. If [Aaron] Judge was having trouble elevating his front shoulder, he’d have trouble getting to pitches up in the zone.” Blewett and I tied our conversation on cortisone shots back to hitting mechanics, with this claim helping to clarify the possibility that Judge’s lack of shoulder health impacted his ability to hit elevated pitches. Among his other ailments from the season’s grind, Judge’s front shoulder remained a central reason for his late-August break.

Unless the Yankees opt for some retrospective transparency on Judge emerging from his slump in the coming weeks, fans will head towards playoff baseball with appreciation for Judge’s rebound, but a dwindling interest in confirming how, or why, he turned the corner. Narratives, like this one, will provide ample food for thought in the meantime, with hopes they corroborate with any revelations.

(Statistics all from open-source platforms,, and GIF created from graph outputs via Thanks to Dan Blewett for taking the time to speak with me.)

Photo credit: Ron K. Murray / USA Today

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