1. 1 What Have We Learned from the PITCHf/x System? A report from the summit What is PITCHf/x and how does it work? What are we learning from it? Outlook for future webusers.npl.uiuc.edu/~a-nathan/pob/pitchtracker.html sportvision.com/events/pfx.html Alan M. Nathan, with help from John Walsh, Mike Fast, Josh Kalk, Dan Brooks, and the good folks at Sportvison, mainly Marv White.

2. 2 PITCHf/x is a pitch-tracking system installed in every MLB venue—a joint venture of Sportvision & MLBAM MLB Gameday ESPN K-Zone Fox Trak

3. 3 How Does PITCHf/x Work? Two video cameras track baseball in 1/60-sec intervals –usually “high home” and “high first” Software to identify and track pitch frame-by- frame in real time  full trajectory  lots of other stuff Image, courtesy of Sportvision

4. 4 What kind of “stuff”? Pitch speed to ~0.5 mph –at release and at home plate (they are different!) Pitch location to ~0.5 inches –at release and at home plate “movement” to ~2.0 inches –both magnitude and direction Initial velocity direction Type of pitch –more on this later And all of this can be correlated with what the batter does! –a complete digital record exists!

5. 5 And the good news is…. …all these data are freely available online! For info on how to download, establish data base, etc., see … –mvn.com/mlb-stats/2008/01/14/a-pitchfx-primer/ Mike Fast –http://brooksbaseball.net/pfx/ Dan Brooks –http://blog.stealingfirst.com/2008/03/07/how-to-link-pitchfx- to-retrosheet/ Dan Turkenkopf

6. 6 What can we potentially learn from these data? Things of interest to physicists –Effect of air drag and spin –The mysteries of the knuckleball Things of interest to players, scouts, fans –What do pitchers thrown and when do they throw it? –What are their most/least effective pitches? –What makes an effective fastball, curveball, slider, …? speed, break, location, … –How do hitters perform against different pitch types, locations, speeds, etc.? –What is effect of pitch sequencing? –Other questions limited only by one’s imagination

7. 7 Example: Pitch Sequence Leading to Bonds 756 th Home Run An obvious mistake: Catcher was set up low and away 1 2 3 4 5 6 7

8. 8 Pitched ball loses about 10% of speed between pitcher and batter Average speed is ~95% of release speed Example 1: Pitch Speed--PITCHf/x vs. the gun PITCHf/x is almost surely more accurate than the gun

9. 9 Example 2: Pitching at High Altitude: Higher, less movement in Denver vs. Toronto 10% loss of velocity total movement 12” 7.5% 8” PITCHf/x data contain a wealth of information about drag and lift!

10. 10 Using PITCHf/x to Classify Pitches Most techniques based on … –Speed –Horizontal and vertical movement due to spin (“pfx”) Same as deviation from straight line, with gravity removed –Examples: FB w/backspin  upward movement CB w/topspin (12-6)  downward movement Sidespin  sideways movement pfx,z pfx,x pfx

11. 11 >90 mph 80-90 mph <80 mph 4-seam fastball 2-seam fastball cutter/slider curveball Wikipedia: Lester, a left-hander, pitches from a low three-quarters arm angle with a deceptive delivery. He features 4-seam fastball (89-95), a cut fastball (86-89), a slider (75-80), a plus-changeup, and a good curveball (72-78 mph). Pitch Classification: LHP Jon Lester, Aug. 3, 2007

12. 12 By comparison, look at Brandon Webb Jon Lester Brandon Webb Plots, courtesy of Dan Brooks Comparing FB upward movement: Lester ~ 11” Webb ~ 3”

13. 13 PITCHf/x tackles the knuckleball – John Walsh Classify pitches using vertical and horizontal break plus speed Compare “normal” pitcher (C.C. Sabathia) with k-baller (Tim Wakefield) “Randomness” of k-ball break is evident in PITCHf/x data Example analysis: What happens when knuckleball does not “knuckle”? Split k-balls into 3 groups – small, medium, large break http://www.hardballtimes.com/main/article/butterflies-are-not-bullets/ fastball curve slider change knuckler Amount of Break Pitches put in play OPS against Small47.979 Medium71.873 Large79.684 http://www.hardballtimes.com (small sample size, though)

14. 14 Josh Kalk, THT, 5/22/08 What makes an effective slider?—C. C. Sabathia This slider is very effective since it looks like a fastball for over half the trajectory, then seems to drop at the last minute (“late break”).

15. 15 Strikes Balls 0 1 2 3 012 0-0 Count, Normal Swing- Zone Width Hitters are more selective when ahead in the count Protecting the Plate When Down 0-2 Analysis by Dan Brooks, brooksbaseball.net Batter Selectivity

16. 16 Scouting Players with PITCHf/x : Roy Oswalt 2008 Mike Fast 4-seam Fastball 2-seam FastballCurveSliderChange LHH 32%29%23%8% RHH 34%28%15%23%0% Total 42136323420447 What is his pitch selection? What are his most effective pitches? Run value/pitch Slider-0.023 Two-seamer+0.007 Four-seamer+0.013 Changeup+0.021 Curveball+0.039 How does he locate his pitches and what results does he get? What do his pitches look like to the batter?

17. 17 low and away high and tight How Fast Should a Fastball Be? – John Walsh http://www.hardballtimes.com

18. 18 From PITCHf/x to HITf/x: Tracking Batted Balls What can be measured with existing cameras? –Speed of ball off bat the ultimate metric of good hitting –Horizontal and vertical angle Together, these highly constrain full trajectory—where does the ball land? –use to evaluate hitting –use to evaluate fielding

19. 19 A computational example: V 0 =90 mph,  0 =35 0 –measured by PFX cameras  = 1462-2284 rpm –not measured by PFX cameras A model for drag and lift landing points differ by ± 4 ft a promising technique

20. 20 Summary PITCHf/x data have the potential to revolutionize the analysis of baseball Some excellent and creative analyses have already been done –Expect more as time goes on Lobby hard for HITf/x, which adds another dimension to the revolution