MLB is throwing sinker again (2021)

This is a post I wrote in July 2021. When I was 18.

Link of the original post: https://blog.naver.com/lgtwinstwin/222450337277


Pittsburgh Pirates increased the frequency of throwing sinkers at the team level to maximize the efficiency of the defensive shift. As a result, during 2013—2015 — for these three years, Pirates advanced to the postseason—Pirates pitched 23.2% of their total pitches as sinker. This was the highest rate of pitching during this period. In the same period, Cleveland Guardians pitched the second most sinker in MLB, their sinker rate was 16.7%.

With the emergence of Statcast and launch angle, hitters tried to hit the ball in the air. More precisely, they avoided ground ball. They upped their swing angle, and sinker - which is a pitch 'sinking' - became a good prey for hitters' swing trajectory. Finally, sinker rate has declined. Pitchers avoided pitching sinker. 

Something is off. Yes, pitchers throw less sinker. But the rate of sinker increased by 8.2%p from 2019 to 2020. It's not temporary. In 2021, the rate decreased little, but this is a number increased by 7.7%p from 2019. The numbers 16.2% in 2020 and 15.7% in 2021 are the first and second biggest since 2008, respectively, on Baseball Savant. What does this mean? MLB has been throwing sinker more than ever since 2008, so why?

What I pay attention to is the movement of the sinker.






The table above shows the average horizontal and vertical movement of the sinker, which is from pitchers who threw more than 50 sinkers. Horizontal movement decreased slightly between 2017 and 2018, but in 2021, 14.9 inches was the biggest number during the recent 5 seasons. 
Vertical movement changed oppositely. In 2017, it was the lowest number, and it increased drastically in 2018 but decreased again.
The table shows us that the sinker of MLB pitchers has changed. Yes, it is marked as the same sinker, but they are different. Horizontal movement is increasing, and vertical movement is decreasing.


And this table shows a grade of the sinker. Well, 0.348 is the lowest since 2018. 
Than why? I thought sinker is not the only pitch in which the rate is increased.


And yes, there was another pitch whose usage increased, too. It was slider and cutter. Especially the usage of slider, whose pitch rate increased from 14.5% in 2008 to 19.2% in 2021, has increased by 4.7%p in 13 years.

Why? Sinker is an arm-side pitch like change-up and four-seamer. Slider and cutter are glove-side pitches. So we can infer that mixing slider and sinker is using two pitches moving in opposite ways. It's a kind of pitch tunneling that puts a focus on horizontal break differences.



The table above shows the average horizontal and vertical movement of the sinker and cutter, which is from pitchers who threw them more than 50 times. And the result was predictable. Their amount of horizontal breaking is increasing, and the amount of vertical breaking is decreasing.

So far, we've only seen a piece of change. These conclusions will be drawn out. 
1. The sinker, slider, and cutter all tend to increase the horizontal movement and decrease the vertical movement.
2. If it is induced intentionally, MLB seems to think that tunneling between different pitches in horizontal breaking is more useful than tunneling between vertically different (ex: high zone fastball & low zone curve). 
3. If it is correct, can I find the cause in the swing trajectory of batters?

And soon, a new pitch came out. Sweeper. I can't confirm that horizontal pitch tunneling is better than others. Pitch tragedy is delicate and complex. It's not a problem that can be solved in black-and-white logic.

댓글

댓글 쓰기

이 블로그의 인기 게시물

Arm angle and Pitcher type

이미지
Danny Young New York Mets pitcher Danny Young’s Baseball Savant movement profile is as follows. He throws a sinker and a sweeper with significant horizontal movement from a low arm angle. He’s a pitcher with an interesting pitch mix. It’s clear that he confuses hitters more with differences in horizontal movement between pitches rather than vertical movement. Horizontal vs. Vertical Movement Differences This gave me an idea. I looked into which pitchers have the greatest differences in horizontal movement and which in vertical movement when pairing their pitches two by two. As previously seen, Danny Young falls into the former category. The image above shows the movement profile of Cubs pitcher Caleb Thielbar in 2020. Unlike Danny Young mentioned earlier, he features a four-seam fastball and curveball combination from a high arm angle. He falls into the latter category, characterized by a large difference in vertical movement. Based on data from 2020 to 2025 for pitchers who faced at l...
자세한 내용 보기

The Relationship Between Pitch Location Scatter Plots and Arm Slot

이미지
During the last offseason, I was looking at a scatter plot of Cleveland pitcher Tanner Bibee’s pitch locations, and it reminded me of a regression line with a negative slope. I had a similar thought after watching Aaron Nola’s knuckle curve location. However, the slope of Nola’s regression line is more gradual than Bibee’s. While this may be the result of various factors—such as the trajectory and usage of breaking balls, as well as command—I focused on something a little different: arm slot. Nola’s average arm slot is 20 degrees, whereas Bibee’s is 51 degrees. And arm slot does have some correlation with pitch movement. I looked into the relationship between pitch location scatter plots and arm slots. Here’s how: •   I plotted pitch location scatter plots for pitchers who threw more than 100 pitches of each pitch type. •   From these scatter plots, I drew regression lines and calculated the location correlation coefficients for each pitcher. •   Then, I compared the corr...
자세한 내용 보기

Randomness of Pitcher

이미지
 The legendary Major League pitcher Warren Spahn once said, “Hitting is timing. Pitching is upsetting timing.” This statement perfectly captures the essence of both pitching and hitting. A pitch that disrupts a batter’s timing is one that is difficult to react to. So, what kind of pitches are hard to react to? It could be an extremely fast pitch, or a very slow one. But more importantly, it could be a pitch that’s difficult to predict. In this article, I use entropy to simply calculate the randomness of Major League pitchers. Method 1 Here’s how I calculated randomness: I calculated the entropy of each pitcher’s pitch usage rates by pitch type. Then, I normalized each pitcher’s entropy score between 0 and 1 to obtain a “pitch usage entropy score.” The more pitch types a pitcher uses, and the more evenly they’re distributed, the higher this score becomes. I selected every pair of pitch types a pitcher throws (for  n  pitch types, there are nC2 combinations), calculated the...
자세한 내용 보기