Rich Hill’s Subtle Change

Written by: Justin Choi (@justinochoi)

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This article is about Rich Hill, but our story begins elsewhere. I had originally set out to discover pitchers whose fastballs were ineffective when thrown up in the strike zone. That seems contradictory, and why I was drawn to it. It’d make for interesting baseball writing. 

As a first step, I used Baseball Savant. I defined the upper part of the strike zone as quadrants 1,2,3 of their ‘gameday zone.’ I then set the requirement to a minimum of 100 results to keep out any outliers, and added wOBA as a measure of effectiveness. Lastly, I limited my scope to 2019, planning to expand it once I had a few candidates. Running the query gave me these pitchers to work with: 

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We have results, but there’s a glaring problem – these pitchers aren’t just bad at throwing up in the zone. Maeda is the lone exception, and Drew Pomeranz’s numbers are inflated by his terrible, pre-reliever days in Boston. The remaining 10 pitchers’ fastballs are ineffective everywhere else in the zone, too. 

Was there any correlation between velocity and up-in-the-zone-effectiveness? Common sense told me no – hitters mustered just a .261 wOBA against Hyun-jin Ryu’s 90-mph high heaters, for example – but to be sure I created a scatter plot showing the relationship between velocity and wOBA: 

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Although there is a negative correlation between fastball velocity and wOBA, the unexplained variance – roughly 94% – shows that the relationship is not concrete. I did this for spin rate, too:

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The correlation, if any, is so weak that graphing a line of best fit is pointless. With my original mission of finding outliers already going awry, I decided to abandon my research and started scrolling down the list of the 179 pitchers before me. 

Then I discovered Rich Hill. 

Hill is one of my favorite pitchers. He used to play for the Dodgers, has an awesome nickname, grunts a lot, and above of all has one of the most inspiring stories in baseball. After life as a journeyman pitcher, Hill ended up playing for an independent league, reinventing himself in the process. The result: 437 innings pitched and a shining 3.00 ERA as a starter for the A’s and the Dodgers between 2016 and 2019. It’s a renaissance so unlikely that it caught many by surprise. 

Rich Hill is also unique in that he’s a rare two-pitch starter. His weapons of choice: a fastball/curveball combo that’s surprisingly dominant, considering that a hitter has a 50% chance of getting it right. The fastball sits at around 90 mph, making it seem harmless, but that spin rate – at 2474 rpm — is one of the highest in baseball. And if that sounds impressive, Hill achieves 100% spin efficiency on his curveball, so yeah, literally pitch-perfect. 

But in 2019, the impenetrable Rich Hill showed signs of weakness. On the high-fastball leaderboard, Hill ranked 28th-worst with a .402 wOBA against, sandwiched between Asher Wojciechowski and Shelby Miller. Hmm, not exactly an elite company. 

Sure, a left forearm strain, which limited him to 58.2 innings this year, probably had a significant influence on this subpar performance. But what surprised me is that his high fastballs have become less and less effective over time. Here’s the wOBA against them by each year since 2016: 

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It’s a mystery. The consistency in velocity and spin rate writes off the explanation of age, a usual suspect, and calls into question whether his injuries were as detrimental as thought. 

So what happened? After a few hours of fruitless foolishness on Baseball Savant, I found another change that correlated with the up-tick in wOBA: 

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The difference is subtle, but from 2016 to 2019, the release points of Hill’s high fastballs have been gradually inching inwards. In addition, the change is noticeable once you look at all his fastballs. Here’s a comparison between the 40-year-old’s release points from 2016 and 2019: 

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Based on the release point data, it seems like Rich Hill had more of a three-quarters delivery back in 2016, whereas in 2019 he chucked his fastballs overhead akin to former teammate Clayton Kershaw. The numbers support this – in 2019, the average vertical release point of Hill’s fastballs, measured as x feet from home plate, was 1.40 ft, very similar to Kershaw’s average fastball release point of 1.44 ft. 

What’s fascinating is that in nine out of ten cases, pitchers’ release points stay consistent with a few year-to-year fluctuations that aren’t markedly deviant. Using Kershaw as an example, the average vertical release points on his fastball from 2016 to 2019 were: 1.12, 1.06, 1.29, and 1.44 ft. Some ebbs and flows, but overall illustrating Kershaw’s pitching motion. 

Rich Hill, however, is a completely different – and more fascinating – story. First, he’s lost nearly half of a foot off his fastball vertical release point. Second, this change is not just occurring to his fastballs. I initially surmised that the decline of his fastball may have been due to the visual separation between his fastball and curveball, leading to fewer deceived hitters. 

But once again, the data surprised me: 

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We can safely conclude that Hill didn’t just make an adjustment to his fastballs – rather, he’s changed his pitching motion entirely. Is that a bad thing? Not necessarily, but the results — or lack thereof — since changing speak for themselves. What’s true is that Rich Hill hasn’t replicated his fabulous 2016 season, which featured pitches thrown the farthest from home plate in the years Statcast data are available. 

However, his 2016 likely had a touch of baseball magic to it; Hill’s true talent is defined by the years afterwards – low-to-mid 3-ERA pitching with an innings limit that keeps him well-rested. It’s not like he suddenly derailed after changing his delivery. 

Okay, here’s where things get even more complicated. Earlier, I noted the correlation between a decrease in vertical release point and a decline in high-fastball effectiveness. Hill’s curveballs invert this relationship. In 2019, he had a career-low wOBA on curveballs thrown in the same ‘gameday zones.’ In fact, the more often he locates up there, the more success he’s had: 

Rich Hill’s curveballs thrown in zones 1,2,3 

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You could chalk it up to a small sample size – Hill doesn’t throw a majority of his curveballs up in the zone, and his 2019 was cut short – but the contrast between his fastball and curveball is nonetheless eyebrow-raising. 

Usually, a breaking pitch up in the zone is a mistake, an ‘oopsie’ that leads to one too many unfortunate home runs. Not for Rich Hill. And here’s another contrast. In 2019, he had just one swinging strike on his high curveballs, courtesy of the swing-happy Kyle Schwarber: 

So why aren’t hitters blasting them away? The answer is they simply can’t, especially if they were expecting a fastball. Hill’s called strike + foul ball rate on those pitches was 60.3%, meaning that hitters either saw them pass by or reacted to them in a pinch more often than not. That’s how you get a stellar .193 wOBA. That part, at least, is no fluke. 

What’s the conclusion? Should Rich Hill go back to his old motion/delivery, or stick with a change he’s been implementing gradually? The answer is that I don’t know. I can’t even be certain that Rich Hill’s subtle transformation is intentional! But for the sake of analysis, let’s say that he’s throwing differently on purpose. Maybe he feels more comfortable doing so. And up until his forearm strain, Hill had been lights-out – a 2.45 ERA across 13 starts. That number might have gone up, might have gone down a la Ryu, but the point is that despite changes his pitching edge has not dulled one bit. Rich Hill should do whatever he pleases. 

As for an explanation as to why his high fastballs performed so poorly, my guess is bad luck. Go by xwOBA and .402 decreases to .330, which is around league-average, and around where Hill has stayed between 2017 and 2018. If that sounds anti-climatic, sorry – I had to draw you in somehow. 

Just like his unconventional mannerisms, repertoire, and career path, Rich Hill’s subtle change is distinctive. It’s surprising that even at age 40, Hill is one of the most intriguing pitchers in baseball, yet it somehow feels like a given. Now that he’s in Minnesota preparing for a new season, we can (hopefully, fingers crossed) find out whether the change discussed thus far is the newest evolution of the man they call Dick Mountain. 

All data and statistics are from Baseball Savant and Fangraphs 

Follow P365 KBO and MLB Analyst Justin Choi on Twitter! @justinochoi

Follow us on Twitter! @Prospects365

Featured image courtesy of photographer Jayne Kamin Oncea and Getty Images 

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