Automated Fastball Velocity Increase Detection

Using baseball-savant data and some Python code, I have written a script that will loop through a pitcher’s three most recent appearances and flag any pitcher who has shown an increase in their fastball velocity. In raw form, it looks something like this:

Looking at the table above we can see that each of these three pitchers increased their fastball (“FF” in savant data) consistently over their last three appearances. Don’t believe me? You can check my work with Savant visualizations:

While I wrote more specifically about the merits of paying close attention to game-by-game fastball increases, quoting many other studies and great pieces along the way, I won’t be writing about it again here. Instead, I’ll simply show you a list of the starters and relievers who have increased game-by-game average velocity on their four-seamers and hope that you can take it from there. Sure, you could scroll through stacks of player pages to find players who have increased velocity until the cows come home, or you could write some code that will detect those increases and flag those players for you. I chose the second way. If you find it useful, I’ll do it on a more regular basis. That’s it. This post is more about the data than the words: