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December 5, 2013

Measuring Pitching with TrackMan

The Secrets of Fastball Spin

by Zach Day

Zach Day was drafted by the Yankees in the fifth round of the 1996 draft and pitched for three MLB teams from 2002 to 2006. He had stints with the Expos, Nationals, and Rockies, compiling a 21-27 record with a 4.66 ERA. Zach has been with TrackMan Baseball since 2008 and has played a critical role in introducing the technology to pitching coaches, scouts, and on-field personnel. This is the first in a series of articles in which he’ll discuss what TrackMan’s measurements reveal about pitching.

Fastball Spin
An average MLB fastball makes 2200 revolutions per minute (RPMs) on its way to home plate. Spin is just one of 27 measurements provided by Trackman’s technology. Trackman’s military grade Doppler radar was introduced to golf in 2003 and first applied to baseball in 2008. Trackman Baseball was officially launched in 2011, and is now being used at the MLB, college, and amateur levels to capture accurate measurements on both the batted and pitched ball as an aid in scouting and player development.

What’s a good fastball spin? As evidenced by the chart below, the spin put on a fastball directly correlates to ground ball rate, fly ball rate, and swings-and-misses. (As for whether high or low spin on a fastball is better—that’s a topic for a different day.) Knowing your spin helps you better understand what type of pitcher you are at present.

Fastball Spin

MLB 2010-2013

RPM (00s)

SwStr%

GB %

<- 20

5.5%

47.3%

20 - 21

6.1%

43.0%

21 - 22

6.8%

40.3%

22 - 23

7.7%

38.7%

23 - 24

8.7%

37.4%

24 - 25

10.4%

36.3%

25 ->

13.4%

37.2%

High-Spin Fastball
Velocity isn’t the only way to get whiffs with the fastball—you can now throw high spin into that equation. “Sneaky” is one of the terms often used to describe a fastball with average to below-average velocity that hitters still swing at and miss at an elevated rate. High spin gives hop or sneak to your fastball. It’s one of the reasons why certain pitchers can throw 90 MPH and still induce a relatively high rate of foul balls and swings-and-misses. Trackman research is now revealing that average fastball spin has a higher correlation to swinging strike rate than average fastball velocity.

The “sneaky” description comes immediately to mind when I think about my former teammate Chad Cordero, and not because of the flat-billed cap hiding his eyes. Hitters would take called third strikes at the knees from Cordero because they were expecting the ball to drop out of the strike zone. His deceptive spin caused hitters to take, swing-and-miss, and foul off what seemed to be an unusual number of pitches. Unfortunately, we don’t have Chad’s spin rate from his 2005 season, when he had 47 saves and a 0.969 WHIP, but Boston’s Koji Uehara is a great contemporary example of a pitcher with a high-spin heater.

Pitcher

MPH

RPM

Average MLB FB

92

2200

Koji Uehara

89

2427

A ball thrown with true backspin that spins at a high rate will work against gravity, causing it to sink less quickly than a ball with lower spin. As a result, hitters’ eyes are deceived, because the ball doesn’t sink as much as they expect it to. No one can defy gravity completely and throw a rising fastball, but pitchers can work with and against gravity as a form of deception.

Want to test this out? Set up a pitching machine to throw an 80 MPH fastball with 3000 RPMs and see how hard it is to hit. Don’t be surprised if you find yourself swinging through and fouling off pitches. You won’t see this offering in actual games—no current pitcher throws a fastball with 3000 RPMs.

Low-Spin Fastball
What makes a fastball “heavy”? As a sinkerball pitcher, I was told I had a heavy fastball. During a complete game against the Brewers in 2003, I induced 21 ground ball outs. The record for ground ball outs recorded in a nine-inning game (since that data began to be collected) is 24, a feat accomplished most recently by Bill Swift in 1988.

Two pitchers who throw 95 MPH can have drastically different spin rates. One may have a fastball with a spin of 2500 RPMs, while the other gets 1800 RPMs. Lower-spin fastballs work against gravity less, causing them to sink at a higher rate than high-spin fastballs.

Have you ever played catch with someone who throws a hard and heavy ball? A low-spin fastball will sink more than you expect and hit your glove closer to the palm of your hand, while a high-spin or even average-spin fastball will more likely hit your glove in the web.

You can lower fastball spin just by changing your grip. A two-seam fastball will have less spin than a four-seam fastball. The same would be true of throwing with one seam or even no seams, which is sometimes called a slip pitch. By splitting your fingers and throwing a fastball, you are effectively taking spin off the pitch and causing it to drop at a higher rate than normal for that velocity.

This could at least partially explain why using spit or Vaseline on a ball can be an advantage. Vaseline would take spin off a fastball, causing it to drop.

Pitcher

MPH

RPM

Average MLB Sinker

91

2070

Jake Westbrook

90

1890

It’s Good to Be Different
Pitchers can benefit from employing an unorthodox approach. A major-league right-handed throwing a 91 MPH fastball with 2200 RPMs out of an average slot (release height, release side, and extension) lacks deception. Hitters’ eyes (and brains) can anticipate how his ball will behave, thanks to their past experiences. Westbrook’s low-spin (1890 RPM) fastball, however, effectively deceives hitters and sinks a little more than the average fastball simply by allowing gravity to work.

2013 Perfect Game WWBA Championships

Pitcher

MPH

RPM

High Spin (90+ MPH FB)

Grant Holmes

92

2432

Kodi Medeiros

91

2398

Jonathan Teaney

90

2389

Low Spin (90+ MPH FB)

Garrett Fulenchek

91

1827

Gray Fenter

90

2102

Anthony Molina

90

2127

Even though spin has been discussed in baseball forever, it’s only recently that we’ve gained the ability to measure it accurately. Knowing what we’ve learned about the effects of fastball spin—Westbrook creates more sink by taking spin off his fastball, while Uehara’s high spin causes his fastball to sink less—we can tell whether a pitcher is a ground ball or fly ball guy, and to what degree, without seeing him throw a pitch. Based solely on Trackman data collected at a Perfect Game event, Howe (TX) High School senior Garrett Fulenchek is an extreme sinkerball pitcher right now. You can see some of the high-spin fastball pitchers from the recently concluded Arizona Fall League below.

Acknowledgments
Special thanks to the Boston Red Sox, St. Louis Cardinals and Perfect Game USA.
Research provided by Josh Orenstein at TrackMan

Avg FB Spin Rate

High Spin Fastballs (AFL)

Parent

Club

Pitcher

Avg

RPM

KC

Jason Adam

2611

SD

Adys Portillo

2578

SF

Adalberto Mejia

2575

PHI

Ken Giles

2553

KC

Malcom Culver

2533

TEX

Matthew West

2507

CLE

Shawn Armstrong

2507

LAD

Yimi Garcia

2504

SF

Kyle Crick

2499

CIN

Michael Lorenzen

2483

TEX

Keone Kela

2470

NYM

Hansel Robles

2465

SEA

Dominic Leone

2463

KC

Angel Baez

2457

TOR

Drew Hutchison

2453

MLB Average

2200

Related Content:  Pitching,  Fastballs,  Spin,  TrackMan

19 comments have been left for this article. (Click to hide comments)

BP Comment Quick Links

jfranco77

Really interesting stuff. Thanks for sharing!

Dec 05, 2013 05:47 AM
rating: 2
 
karp62

Great analysis, yet easy to read and understand. Thank you Zach.

Dec 05, 2013 05:58 AM
rating: 3
 
Shawn

Right now, is all TrackMan spin data considered proprietary for the teams that have purchased the technology?

Assuming yes, are there any data sets at all in the public domain or scheduled to be in the near future?

Dec 05, 2013 06:07 AM
rating: 1
 
jorens

TrackMan data is generally proprietary to the teams we work with. We have released some data in the past through various sources.

Josh Orenstein
Trackman

Dec 05, 2013 08:27 AM
rating: 1
 
Noel Steere
(965)

Really good stuff! If you post another article, could we see a similar table to the RPM/swing rate/GB rate, but using both RPM and MPH as variables? Could indicate what the ideal velocity is for high and low spin pitches.

Dec 05, 2013 06:18 AM
rating: 0
 
Dave from Pittsburgh

This is awesome, I wonder where Tanaka would fit on this article?

Dec 05, 2013 08:35 AM
rating: 0
 
jdeich

Great article!

I assume that while you're recording the rate of spin, TrackMan also records the orientation of the axis of spin. Any chance of a "spin-off" article on how that impacts results?

Dec 05, 2013 09:02 AM
rating: 0
 
jorens

We do record spin axis, which definitely has an effect on outcomes. Plan was to do the next article on curve spin and then one on extension and go from there. Any feedback is appreciated. If you have questions for Zach, I can pass them along or you can find him on twitter.

Dec 05, 2013 09:16 AM
rating: 1
 
Bryan Cole

Further reading: David Kagan just wrote a post on The Hardball Times on the physics of what makes a sinker feel "heavy" (spoiler alert: it involves spin).

http://www.hardballtimes.com/main/article/why-is-a-sinker-heavy/

Dec 05, 2013 09:36 AM
rating: 1
 
JohnChoiniere

God I wish Trackman data were public. True spin axis/RPM looks like the last missing piece of being able to automatically classify pitches accurately.

Dec 05, 2013 09:40 AM
rating: 1
 
Alan Nathan

Just to clarify, TrackMan does not measure the "true spin axis". It is determined from the measured movement of the pitch, just like it is done with PITCHf/x. However, it does measure the true rate of spin (rpm's), unlike PITCHf/x. I wrote an article about the spin axis for my web site a couple of years ago: http://baseball.physics.illinois.edu/trackman/SpinAxis.pdf

Dec 06, 2013 10:34 AM
rating: 0
 
BP staff member Dan Brooks
BP staff

Serious question, not trying to be difficult: the majority of fastball spin is on-axis and creates movement, right? If that's the case, why do we need to use Trackman numbers to do this analysis?

Dec 05, 2013 10:09 AM
 
Alan Nathan

Good question, Dan.

Dec 06, 2013 10:35 AM
rating: 0
 
MikePemulis

Not sure I understand Dan's question. Even if a fastballs rotation is on axis would not the rate of rotation affect the amount of movement? Or are you saying that if fastballs essentially have the same plane of movement (all things being equal - arm slot, velocity, etc), that the sink or 'rise' of a fastball can be measured by its observable results (swinging strike %, gb rate, etc.) and therefore trackman is just putting an RPM to a phenomenon we can already measure by its outcomes?

Dec 05, 2013 12:10 PM
rating: 0
 
Alan Nathan

See the link I just posted: http://baseball.physics.illinois.edu/trackman/SpinAxis.pdf.

Dec 06, 2013 10:36 AM
rating: 0
 
BP staff member Dan Brooks
BP staff

Sorry. The point was that the majority of spin on a fastball is directly proportional to it's movement. This allows us to calculate RPM using formulae provided by Alan Nathan (that are now included in the Pfx datafiles).

Unlike, say, a slider, which spins quite a bit, but because most of that spin is gyro spin, it will be difficult to capture with a non-trackman system.

Dec 05, 2013 12:16 PM
 
MikePemulis

Got it. Makes sense. Thanks for clarifying.

Dec 05, 2013 12:19 PM
rating: 0
 
Llarry

If nothing else, fastballs make a good "sanity check" for the system. It's also the best pitch to introduce it with, as the results are more straightforward.

This was awesome. Thanks for showing it off. I understand that you may have a lot of proprietary data, but I really appreciate understanding the process, even if I don't get to see all the final numbers.

Dec 05, 2013 12:33 PM
rating: 0
 
Alan Nathan

Zach...I'd like to discuss some of your analysis with you privately. Would you contact me (a-nathan@illinois.edu). Thanks.

Dec 11, 2013 11:44 AM
rating: 0
 
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