Fun with Pitch F/X Leaderboards Part 2: The Breaking Balls

Welcome to Part 2 of my series of posts exploring the best pitches in baseball using the Pitch F/X Leaderboards.

If you’ve never played around with the Pitch F/X leaderboards at Baseball Prospectus, what are you waiting for? They have a wealth of information about pitchers that you can’t easily find anywhere else. Because there is so much information we can gather from these leaderboards, I’m devoting a multi-part series of posts to them.

We’re going to dive into the tables and look at the leaders in key metrics that relate to success as a starting pitcher. This means getting whiffs, good movement on your pitches, getting ground balls, and getting pop-ups, to name a few. Today, we’re going to focus on breaking balls. Who has the best slider in each of those metrics I just mentioned? How about the best curve ball? I’m just going to show you the top 25 in each for simplicity, but check out the leaderboards yourself if you want more.

I’m hoping that filtering this information into bite-sized pieces will help you as you evaluate pitchers for your fantasy team. The specific stats I will be using are: horizontal pitch movement, vertical pitch movement (these are both in inches and relative to a ball with no spin), whiffs per swing, ground balls per ball in play, and pop-ups per ball in play (which are basically automatic outs).

At the end of this post, I will round up a list of the guys that have the best sliders and curves, by looking at who shows up on these top-25 tables the most times for each pitch. Let’s go ahead and get to the tables.

Who would have guessed Jhoulys Chacin would have one of the best sliders in baseball? I liked him early this year with increased velocity and more strikeouts, but that has disappeared, despite the great slider. I think we can all move on.

Severino has a good fastball and a great slider. He still has great potential if he can put it all together when he gets back to MLB. I think he's still a buy low. Rubby de la Rosa is in a similar boat (but also injured). He has some great weapons and velocity, but can't command them. There's still hope there, but I think I prefer Severino as a long shot.

Dallas Keuchel's command has hurt him this year, not his slider. He's not as bad as his ERA (his xFIP is a decent 3.56), so I think he's a buy-low, but he's not the Cy Young guy we knew anymore. Jon Gray is possibly the best Rockies pitcher in years, so he might be the first one worth rostering in a while. The home park will always be an issue, but the skills and peripherals say he could be a 3.5 ERA pitcher.

Who knew Kershaw and Syndergaard had good sliders? Oh, yeah, everyone.

Julio Urias is looking impressive. His fastball showed up in Part 1 and now here's his curve. That's definitely a good sign for such a young star. We have reason to be excited about him. Jose Fernandez is known for his elite curveball, so no surprise there.

Drew Smyly showed up twice on the fastballs list in Part 1 and his curve pops up here. He's got all the pitches he needs, but the home runs and health are holding him back. He could be a 3.2 ERA guy with great strikeout rates if he could put it all together.

Aaron Sanchez is in a legit breakout season and looks like more than just a reliever masquerading as a starter. His curve belongs on this list. Alex Wood is unfortunately hurt after righting the ship, but he's still got the tools necessary to do well once he's healthy. I just wrote about Robbie Ray recently and his maddening combination of great "stuff" and bad results.

I'm ignoring Bettis and Morton, despite their great curves, because the rest of their stats say "stay away"!

Check back soon for Part 3: The Off-speed Pitches. Tschus!