Introducing: Pitch Plot Generator
Also, an aside about Nick Pivetta
Max Bay made a super cool app this week. It lets you see how much each pitcher’s four-seam fastball deviates from its theoretical “dead zone.” By showing the expected movement of the pitcher’s fastball based on their arm angle, and then showing how the actual movement of the pitch compares to the “expected” movement, it puts the pitcher’s fastball in context. A fastball is only as good as the hitter perceives it to be.
I tweeted about Nick Pivetta’s dynamic dead zone because it shows why Pivetta’s fastball isn’t as amazing as you might assume by just looking at its transcendental vertical break numbers. Every season of his career, Pivetta has posted an above-average home run rate. That’s not a coincidence — there is something about the fastball that hitters can track, especially when facing Pivetta for the second or third time in a start.
Max’s app points to what that something might be. Pivetta is 6-foot-5 and has a super vertical arm angle. Hitters expect tons of carry from that release position, and so the fastball doesn’t play as much as you might expect given the raw iVB numbers.
Anyway, Max’s app is hosted on Streamlit. Lots of super impressive Streamlit apps are on the baseball internet these days. Twitter user @sunshinevvn made one. Thomas Nestico made one. I think Kyle Bland is the guy who made Streamlit cool; he has a bunch of apps up as well. (Sorry if I’m missing somebody.)
As a challenge to myself, I tried to make my own Streamlit app. And it worked! It’s called the Pitch Plot Generator and it generates a pitch plot for any pitcher that’s thrown a pitch in 2024. (Try it here.)
The appeal of Streamlit is that it’s supposed to make everything easy — for me, it was not so easy, but on the other hand I was an English major. So don’t expect anything groundbreaking — mostly, I just wanted to see if I could do it. But I’m finding it useful so far and maybe you will too.
Before I made this app, every time I wanted to look at a pitch plot — if I was curious about a pitcher I’m watching, maybe, or if I was doing research for my fantasy baseball waivers — I had to open the Terminal on my computer, fire up Jupyter Notebooks, download every pitch from the 2024 season, and then finally query a plot of the pitcher I wanted to see.
That was really annoying. So I made this app to quickly pull up a specific pitcher’s pitch plot. Some fun plots…
Craig Kimbrel!
Nick Pivetta!
Bryce Miller!
Whatever pitcher you want to see from the 2024 season, they’re on the app. I’ll link it again here — it probably works best on desktop, but it will work on your phone too. In a perfect world, I’d add a legend explainer (FF = four-seam fastball, KC = knuckle-curve, etc.) and summary statistics on each pitch: vertical break, horizontal break, velocity, usage percentage, and so on. But I’m not going to do that! I only made this because I was procrastinating on something else. So I hope you like it as is.