Loves Aaron Judge
- Feb 4, 2012
I've never seen "SWEEPER" as a pitch category before.
Your last sentence got me thinking….did Byung Hyun Kim throw a sweeper from that lower arm angle? I remember his “slider” being very horizontal. And DiceK I recall having the a version of his slider that was like a “frisbee” ball as Jerry Remy used to describe it.Breaking out from the April 30 game thread.
Judging by Bryce Miller's demonstration grip, the sweeper is a knuckle slider that sacrifices velocity for increased horizontal movement.
Back in the days of DiceK, I used to call that pitch a slurve, but Youkilis insists that the slurve has more vertical drop, while the movement on the sweeper is almost entirely horizontal.
I'm afraid that I don't have time for a very long answer here, but one way to characterize the difference is in the direction of the ball's spin. The direction of the break is given by the cross-product of the spin axis and the ball's velocity toward the plate. You can find some diagrams that will explain this atI've always understood that curveballs break down and are thrown with the fingers on the front of the ball, with the arm bent at the elbow. In contrast, sliders are thrown with the fingers on the side of the ball, full extension, and have more of a flat break (horizontal), and slurves (a combo of the two) are to be avoided (righty v righty and left v lefty), since the break lines up with the swing angle of the batter.
But, I'm reading that a slider has "gyro" spin while a sweeper relies on "seam-shifted wake" and I'd love some explanation on the difference of those two things.
Thank you for the video.I had a minute to dig around and found this really helpful write-up addressing seam shifted wake, which appears to not be primarily created by a particular spin axis but by airflow patterns created by seam positioning. My overly simplified summary is the sweeper is a slider with the seams held in such a way as to create disruptive airflow around the ball that results in a larger break:
"The action on this pitch is much better than the traditional slider. The only downside is velocity, with the Sweeper going about 3.2 MPH slower on average than the traditional slider in 2021. Yet, speed was never the point of an effective slider - last year's data suggests the Sweeper spins 125 more RPMs than the regular version of this pitch. This causes more break, with the regular slider breaking 7 inches horizontally and the Sweeper breaking 15 inches (a roughly 114% improvement). But while spin is important in some cases, the deadliness of this pitch is not entirely caused by the high spin rate. It is owed to a newer scientific concept that is breaking the way physicists think of pitching.
Introducing Seam-Shifted Wake - the cause of this absurd pitch. Originally discovered by Alan Nathan using Pitch F/X Data (the private version of MLB data before Statcast), he found that the degree of late movement that certain pitches have are not owed to the regular concepts of pitching. To properly explain this, I will attempt to boil down the science behind the concept, as I believe knowing that is incredibly important in understanding how this pitch is physically possible. When a regular pitch is thrown, it is usually subject to a “Magnus” effect - a pitch moves based on how the ball is being held and the slip of the fingers behind the spin. Regular pitches are under the influence of this effect, spinning in the same manner from the pitcher's hand to the plate, moving as when the ball left the hand. The Sweeper, and other pitches that are prone to seam-shifted wake, are not limited to this Magnus. Instead, they experience a state of Non-Magnus. When under this state, a pitch can gain free movement, curving and moving in ways that didn’t come originally from the hand grip. In a sense, the ball appears to be moving on its own. But it’s not - it’s experiencing a heavy dose of Seam-Shifted Wake."
This video is from 3 years ago- really fascinating: