The skinny on the pitch that's taking baseball by storm.
Would you be surprised if I told you that over a quarter of the curveballs delivered by major league pitchers in 2013 were thrown with a knuckle curve grip? I certainly was. This was one of the results of the first comprehensive study of knuckle curveballs in the major leagues, which I have conducted after months of data collection. It is limited to PITCHf/x data, but the large population sizes give us a good first look at what knuckle curveballs behave like relative to standard curves.
What is a knuckle curveball?
First, let me define clearly what this study entails. A curveball is a pitch that, when thrown from a conventional arm angle, will drop from its normal trajectory due to topspin. It is also typically thrown slower than other pitches, so it drops significantly from the effect of gravity, as well. The two most important fingers in the curveball grip are usually the middle finger and the thumb. The middle finger and thumb rest on or beside seams on opposite sides of the ball, as in this image. At release, the thumb and middle finger spin the ball forward, giving it the desired topspin. The index finger is not needed at all to throw the pitch, and a handful of pitchers even leave it off the ball entirely.
Clay Buchholz is known for throwing a nasty changeup, but he's added a new off-speed pitch to his arsenal in 2012.
Clay Buchholz has added a splitter this year to go with his well-known (and devastating) changeup. We first noticed this back when he was throwing one or two per game, but now it’s not unusual to see him throw a nice cluster of splitters in each start. A comparison between his pre-splitter and post-splitter pitch graphs is shown below:
Wrapping up Kevin's scouting primer with a look at how pitchers are evaluated.
While looking toward the future with our comprehensive slate of current content, we'd also like to recognize our rich past by drawing upon our extensive (and mostly free) online archive of work dating back to 1997. In an effort to highlight the best of what's gone before, we'll be bringing you a weekly blast from BP's past, introducing or re-introducing you to some of the most informative and entertaining authors who have passed through our virtual halls. If you have fond recollections of a BP piece that you'd like to nominate for re-exposure to a wider audience, send us your suggestion.
Revisit the third and final part of Kevin's scouting vocabulary primer, which covered the qualities evaluated when a scout looks at each of a pitching prospect's offerings. The piece was originally published as a Future Shock column on March 16, 2006.
A primer on how pitchers produce movement and vary velocity by gripping and releasing their pitches.
Pitching mechanics tend to dominate the word count here in Raising Aces, so it may surprise some readers to learn that my favorite element of pitching is “stuff.” Nothing lights me up like blazing heat, baffling change-ups, and exploding sliders that paint a catcher's target. Some pitches are so devastating as to take on a personality of their own, effectively defining a player's legacy, such as the cutter of Mariano Rivera or the change-up of Johan Santana. There are even pitches that are so legendary that their reputations have survived the passage of time, to be appreciated by people who never personally witnessed their glory, including Walter Johnson's eye-blink heater and Sandy Koufax's knee-buckling curve.
The quality of a pitcher's stuff is intertwined with his mechanics. Pitch velocity is determined by kinetic energy that is transferred through linear momentum, torque, and the rotational elements of the delivery. Pitch command is directly tied to the consistency of mechanical timing and sequencing, in addition to dynamic balance and posture. The key ingredient to pitch movement is also rooted in mechanics, and though a pitcher's grip on the baseball tends to steal the spotlight, the more critical determinant of pitch break is the angle of the pitcher's forearm at release point.
What factors determine how often hitters take one for the team?
Every season major league pitchers throw tens of thousands of pitches inside off the plate, yet they hit batters “only” about 1500-1800 times in a season. Why do some inside pitches hit the batter, while others do not?
A new season brings a new batch of PITCHf/x data from which to learn.
"With me, being a hard thrower ... no matter what, they're defending that heater, man. So the more confidence I have to throw that [changeup] in any count, I'm going to throw it. I'm just going to. I don't care anymore. It's going to help me and I realize that." --A.J. Burnett on his pitch selection. PITCHf/x has confidence in his fastball as well.
Popping the hood on King Felix as a demonstration of what's possible with PITCHf/x data
"Hell, yeah, I want to throw that pitch. They don't let me, though. They tell me I'm too young, that it's bad for my elbow. I told them I want to throw it."
--Felix Hernandeztalking about his slider before the 2006 season