Imagine Yusmeiro Petit with Velocity?

Of starters who have thrown a fastball at least 200 times this year, Yusmeiro Petit’s average velocity (89.13 MPH according to Baseball Pro’s Pitchf/x leaderboard) comes in at #167 of 173. Yet, only Clayton Kershaw, Chris Sale and Yu Darvish have better K-rates than him. Only Kershaw, Francisco Liriano, Masahiro Tanaka, Sale, Tyson Ross and Carlos Carrasco have a better swinging-strike rate than him in general.

Not only has Petit been dominant (from a strikeout perspective), but he’s also been downright commanding: 4.3 BB% resulting in the #3 overall K%-BB% rate in baseball for starters (24.1%) – again, only behind Clayton Kershaw and Chris Sale.

How on earth can Petit approach Kershaw and Sale from a strikeout/swinging-strike perspective? The first thing I looked at was their release point consistency using root-mean-square deviations thinking this could have some impact with his Fastball-Cutter-Changeup repertoire, which supports his actual bread-and-butter breaking ball. My thought was that visually, Petit’s release point looked very consistent relative to Kershaw’s and Sale’s. Take a look at his fourseamer, cutter and change in basically one blotch:

Petit's Release Point Consistency excl. CB
Petit’s Release Point Consistency excl. CB

To verify, I downloaded the Baseball Savant Pitchf/x CSV dumps for Kershaw, Sale and Petit and removed all pitches that were greater than 6 inches from the mean either horizontally or vertically. Kershaw unfairly had the best RMSE of the three at .21 which was about 14% better than Petit’s rate. Petit was about 17% more consistent than Sale. This might have some impact allowing Petit to approach Sale’s contact rate (73.6% vs. 73.1%), however…

It’s all about Petit’s sweeping curve. Eno pointed this out way back in May. It actually led me to pick him up in my deepest dynasty league way before anyone else would have even remotely thought about adding him. He joined a cluster of other high K/9 relievers on my team (Boxberger, Giles, Allen and Uehara). Recently, outside of a start in Colorado, he has greatly rewarded his owners. Since 8/23, in 30.1 IP, he’s only given up 23 hits (11 ER) with a 36:1 K/BB ratio. Based on his LOB% and HR/FB rates i.e. the start in Colorado, we might even consider him unlucky. His ERA of 3.26 over this time is backed-up and then some by the 2.16 xFIP.

With a 100-pitch qualifier, Yusmiero Petit’s Curve has the 4th best whiff/swing rate in the game – just above Jose Fernandez for reference (alright… I won’t neglect noting that Gavin Floyd and Trevor Cahill are the top two). Applaud it. He does. Dee Gordon should. His Cutter is just above average while his more scarce Change is just below average, but they both still induce whiffs at 22% and 27% of the time respectively this year.

This is a great post reviewing his 1-hit shut-out of the D-back last year from Carson Cistulli with an epitomizing GIF of each pitch.

Now again, imagine him with velocity? Based on the components, expect a 3.55 ERA with 145 K’s next year if he remains a starter, but sit him when rational. We now have two seasons plus his 2012 AAA PCL performance to back it all up.


Daniel Schwartz contributes for RotoGraphs when he's not selling industry leading thermal packaging. You can follow him on twitter @RotoBanter

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Big Head Bochy
9 years ago

Not an analytics guy here and I’m a big hung-over. Just want to make sure I get your gist here: Petit will continue to fool people due to his pin-point perfect (all the dots align) release point. So, Petit is not a one-trick pony who’s curve will get smashed with more exposure?

Also, is he guaranteed a rotation spot? Bumgarner, Peavy, Cain, Lince ______?