Arm Slots Revisited
Matt Lentzner
About Me
•My main interest is in physical computersimulations. Tried to do a baseball simulationand realized that baseball was not as wellunderstood as I had assumed. Trying to figurethis stuff out really caught my interest.
Goal
•Qualitatively model how arm angles affectpitching
Easy Quiz
•What pitch is the most basic and elemental ina pitcher’s repertoire?
•What pitch is typically thrown with the mostvelocity?
•What pitch has the most break?
The Fastball
•The reference point for all pitching because itis the most efficient.
–Most Velocity
–Most Spin
–Least Taxing to Throw
•Most importantly it is thrown “inline” with thearm. The spin is aligned to the arm slot.
The Thesis
Using a horizontal/vertical scatter plot of pitchmovement:
A line drawn from the origin (0,0) to the fastballcluster will describe the arm slot.
Jonathan Papelbon
Hideki Okajima
Brad Ziegler
All other pitches work off the Fastball
Fastball (-0 mph)
Splitter (-5 mph)
Change Up (-9 mph)
Sinker (-3 mph)
Change Up (-9 mph)
Cutter (-3 mph)
Slider (-7 mph)
Slurve (-10 mph?)
Curve (-13 mph)
The Pitching Peanut
(high ¾ arm slot)
Is there a practical value to allthis?
Pitch Typing without Arm Slots(This only works with high 3/4 arm slots)
How you do Pitch Typing using armslots
•Pitch Identification
–Use the technique in reverse: know ahead of timewhat the arm slot is and apply the template
–Even pitchers who don’t throw a in game fastballcan still be ID’ed once you know the arm slot
Derek Lowe
Roy Halladay
Josh Beckett
Johan SantanaJust Flip the Peanut for Lefties
How to ID Pitches
ID the pitch byoffset angle
Is it a fastball,sinker, orchangeup?
Yes
No
Use offset ID
Compare pitch speedto determine if achangeup or splitter
Questions?
Spins
Fastball
Cutter
Slider
Slurve
Curve
Sinker
Estimating Arm Slot from PITCH f/x release points(as opposed to scouting it)
•Lots of problems
–Stride Length
–Posture
–Position on Rubber (24” wide)
–Listed heights (which imply arm length) are notaccurate (especially for vertically challengedplayers)
•On the plus side we don’t need high precision
Jonathan Papelbon6’4”
Brad Ziegler6’4”
