PitchGrader AI Data Glossary

Comprehensive definitions for all baseball data metrics and pitch analysis terms

PitchGrader Pitch Shape Metrics

These advanced metrics are unique to PitchGrader and provide comprehensive pitch classification based on 3D movement analysis.

Pitch Shape Tilt
The angle of the ratio of the 2-plane movement, as used in Pitchgrader. This accounts for 2 of the 3 axes in the 3D space. Note that "Pitch Shape Tilt" is very different than "Pitch Spin Tilt" - they describe very different things.

Pitch Shape Tilt uses the horizontal and vertical movement of the pitch to determine an angle representing the 2-plane movement in the X/Z direction. By its nature, the release velocity naturally has an effect on the vertical movement, thus affecting this angle too, because slower pitches give gravity more time to pull them down.

Interpretation: Negative angles indicate break towards 1st base side, and positive angles are towards 3rd base side.
Pitch Shape Depth
Some pitches have similar or overlapping Pitch Shape Tilt, so we use the amount of break along the Pitch Shape Tilt angle to separate the pitch types. This isn't simply adding the vertical break and horizontal break, but uses standard Pythagorean Theorem to find the magnitude of the break along the angle produced by the horizontal and vertical break.

The magnitude of the break along the Pitch Shape Tilt angle is Pitch Shape Depth. This metric has been used in Pitchgrader for years to distinguish between pitch types with similar tilt angles.
Pitch Shape Sharpness
Pitch Shape Sharpness is the sharpness of the break in the Y and Z direction. The Horizontal and Vertical approach angles and Horizontal and Vertical release angles represent the sharpness. Higher sharpness means higher angles, more movement. If a pitch has low sharpness, it is usually a higher velocity pitch.

The Pitch Sharpness further defines the characteristics for a pitch in the Y/Z direction. For example, a Slider is always a slider because of the Pitch Shape Tilt and Pitch Shape Depth values. Whether it has sharp Y/Z break for Pitch Sharpness will affect if it's called a "Slider" or "Power Slider".

This accounts for the last 3rd of the 3-axis 3D space. To simplify, this is a sharpness number derived from those metrics, like a "Q" factor for an inductor used to define sharpness of a filter in electronics. The "Pitch Sharpness" is the absolute number values of Horizontal approach angle minus horizontal release angle and Vertical approach angle minus vertical release angle, added together. The result is multiplied by 10 to scale up to be in the range of Pitch Shape Tilt and Pitch Shape Depth to make 3D charting easier.
Pitch Shape Type
Categorizes pitches into groups based on using all 3 of their Pitch Shape Tilt, Pitch Shape Depth and Pitch Shape Sharpness values. This comprehensive classification system provides more accurate pitch type identification than traditional methods by analyzing the complete 3D movement profile of each pitch.

Game Context & Sequencing

PitchNo
The current pitch number. Sequential ordering of all pitches in the game.
Date
The date of the current pitch. Date of release of ball from pitcher's hand (local time).
Time
The time of the current pitch. Time of release of ball from pitcher's hand (local time).
PAofInning
The current plate appearance number of the current inning. Each plate appearance contains 1 or more pitches. Indication of the batting order of the half inning where the first batter is assigned a 1, the second batter a 2, etc.
PitchofPA
The pitch number of the current plate appearance. Indication of the pitch of the plate appearance whereby the first pitch of the at bat is assigned a 1, the second pitch a 2, etc.
Inning
The current inning number.
Top/Bottom
The Top or Bottom of the current inning.
Outs
The number of outs in the current inning.
Balls
The number of balls in the current count.
Strikes
The number of strikes in the current count.

Player Information

Pitcher
The name of the current Pitcher. Last name, first name.
PitcherId
The ID number of the current Pitcher. MLBAM ID of pitcher.
PitcherThrows
The handedness of the current Pitcher. "Right" means right handed or RHP. "Left" means left handed or LHP.
PitcherTeam
The team that the current Pitcher belongs to.
PitcherSet
The set position of the current Pitcher.
Batter
The name of the current Batter. Last name, first name.
BatterId
The ID number of the current Batter.
BatterSide
The handedness of the current Batter. "Right" means right handed or RHB. "Left" means left handed or LHB.
BatterTeam
The team that the current Batter belongs to.

Pitch Classification & Results

TaggedPitchType
The pitch type as determined by manual tagging.
AutoPitchType
The pitch type as determined by automatic tagging.
PitchCall
The result of the pitch. Indication of: Strike [called, swinging]; Ball [called, intentional]; (pitchout is considered an intentional ball); Hit by Pitch; Foul, or; In Play.
KorBB
Whether the pitch result was a walk, strikeout, or "Undefined" equals not a walk or a strikeout. Indication of 3rd strike or 4th ball of an at bat.
HitType
If the ball was hit, then shows the type of hit. If "undefined" then the ball was not hit.
PlayResult
If the ball was hit, then shows the result of the hit. If "undefined" equals ball was not hit. Single; Double; Triple; Homerun; Reached on Error; Fielder's Choice (No Out Recorded); Out; Sacrifice; Undefined (if ball is not put In Play).
OutsOnPlay
If the ball was hit, then shows the number of outs that resulted. Number of outs recorded on that pitch (0, 1, 2, or 3).
RunsScored
If the ball was hit, then shows the number of runs that resulted. Number of runs scored on that pitch.

Release Point & Velocity

RelSpeed
The pitch release velocity of the current pitch. Speed of pitch, reported in miles per hour, when it leaves the pitcher's hand.
VertReleaseAngle
The pitch vertical release angle of the current pitch. Initial vertical (up-down) direction of the ball when it leaves the pitcher's hand, reported in degrees. A positive number means the ball is released upward, while a negative number means the ball is released downward.
HorzRelAngle
The pitch horizontal release angle of the current pitch. Initial horizontal (left-right) direction of the ball when it leaves the pitcher's hand, reported in degrees. A positive number means the ball is released to the right from the pitcher's perspective, while a negative number means the ball is released to the left from the pitcher's perspective.
RelHeight
The release pitch height of the current pitch. Height, reported in feet, above home plate at which the pitcher releases the ball.
RelSide
The pitch release side of the current pitch. Distance from the center of the rubber, reported in feet, at which the pitcher releases the ball. Balls thrown from the right side of the mound from the pitcher's perspective will have a positive number, and balls thrown from the left side of the mound from the pitcher's perspective have a negative number.
Extension
The pitch release extension of the current pitch. The distance, reported in feet, from which the pitcher releases the ball relative to the pitching rubber.

Spin & Movement

SpinRate
The pitch Magnus spin rate of the current pitch. How fast the ball is spinning as it leaves the pitcher's hand, reported in the number of times the pitched ball would spin per minute ("revolutions per minute" or "rpm").
SpinAxis
The pitch Magnus spin axis of the current pitch. Direction the ball is spinning, reported in degrees of tilt. Note: A ball thrown with a spin axis of 0 has pure top spin (classic "12-6" curveball). A ball thrown with a spin axis of 180 has pure backspin (classic four seam fastball). A ball thrown with a spin axis of 90 is spinning squarely toward the left, from the pitcher's perspective (break to the left), while a ball thrown with a spin axis of 270 is spinning squarely toward the right (break to the right).
Tilt
The pitch Magnus spin tilt of the current pitch. Spin axis converted into clock time, rounded to the nearest 15 minutes. As a rule of thumb, the ball will break in the direction of the number on the clock face. For example: 6:00 is perfect top spin (classic "12-6" curveball), causing the ball to break down; 12:00 is perfect back spin (Four seam fastball), causing the ball to break upward relative to gravity alone; 3:00 is a "Frisbee" spinning and breaking to the right, while 9:00 is a "Frisbee" spinning and breaking to the left.
VertBreak
The pitch vertical break of the current pitch. Distance, measured in inches, between where the pitch actually crosses the front of home plate height-wise, and where it would have crossed home plate height-wise if it had traveled in a perfectly straight line from release, completely unaffected by gravity. Note: This number will be quite large for pitches released with a positive vertical release angle.
InducedVertBreak
The pitch induced vertical break of the current pitch. Distance, measured in inches, between where the pitch actually crosses the front of home plate height-wise, and where it would have crossed home plate height-wise if it had traveled in a perfectly straight line from release, but affected by gravity. Note: If this number is positive, the ball broke "upwards", or in reality dropped less than it would have due to gravity alone.
HorzBreak
The pitch horizontal break of the current pitch. Distance, measured in inches, between where the pitch actually crosses the front of home plate side-wise, and where it would have crossed home plate side-wise if it had traveled in a perfectly straight line from release. A positive number means the break was to the right from the pitcher's perspective, while a negative number means the break was to the left from the pitcher's perspective.

Plate Crossing & Approach

PlateLocHeight
The pitch plate vertical location of the current pitch. The height of the ball relative to home plate, measured in feet, as the ball crosses the front of the plate.
PlateLocSide
The pitch plate horizontal location of the current pitch. Distance from the center of the plate to the ball, measured in feet, as it crosses the front of the plate. Negative numbers are to the left of center from the pitcher's perspective (outside to a right handed batter). Positive numbers to the right of center from the pitcher's perspective (inside to a right handed batter).
ZoneSpeed
The pitch plate velocity of the current pitch. Speed of the pitch, measured in miles per hours, as it crosses the front of home plate.
VertApprAngle
The pitch vertical approach angle of the current pitch. How steeply up or down the ball enters the zone, reported as the angle, as the pitch crosses the front of home plate. A negative number means it is sloping downward, while a positive number (rare) means it is sloping upward.
HorzApprAngle
The pitch horizontal approach angle of the current pitch. Left-right direction at which a pitched ball crosses the front of home plate, reported as an angle. A negative number means that the ball is moving from right to left from the pitcher's perspective (away from a right handed batter) as it enters the zone, and a positive number means that the ball is moving from left to right from the pitcher's perspective (in on a right handed batter) as it enters the zone.
ZoneTime
Amount of time elapsed from pitcher's release until it crosses the front of home plate. Also, may be referred to as "batter reaction time", the pitch time to plate of the current pitch.

Batted Ball Metrics

ExitSpeed
The speed of the ball, measured in miles per hour, as it comes off the bat at the moment of contact, the exit velocity of the batted ball, if the ball was hit for the current pitch.
Angle
How steeply up or down the ball leaves the bat, reported as an angle. A positive number means the ball is initially traveling upward, while a negative number means the ball is initially traveling downward, the launch angle of the batted ball, if the ball was hit for the current pitch.
Direction
Left-right (horizontal) direction in which the ball leaves the bat, reported as an angle. A negative number represents a ball initially traveling toward the third base side of second base while a positive number represents a ball initially traveling toward the first base side, if the ball was hit for the current pitch.
HitSpinRate
How fast the ball is spinning as it leaves the bat, reported in the number of times the hit ball would spin per minute ("revolutions per minute" or "rpm"), the spin rate of the batted ball, if the ball was hit for the current pitch.
Distance
The estimated "carry flat" distance, measured in feet, meaning the distance that the ball travels before it lands, or would have landed if it were not caught or obstructed, if the ball was hit for the current pitch.
Bearing
Indicates where on the field the ball lands or would have landed, had it not been caught or obstructed. It is reported in degrees relative to home plate. A bearing of 0 degrees means the ball landed on a straight line from home through second base. A positive number means the ball landed on the first base side, while a negative number means the ball landed on the third base side, if the ball was hit for the current pitch.
HangTime
Amount of time, measured in seconds, elapsed from when the ball hits the bat until the ball lands or would have landed, had it not been caught or obstructed, if the ball was hit for the current pitch.
LastTrackedDistance
The distance, measured in feet, that the radar actually tracks the ball. In some cases, the radar tracks the ball only for a portion of the hit trajectory and in this case the remaining part of the trajectory is estimated by the software using a ball flight model. This means that the Distance and Bearing reported by TrackMan is partially estimated and can have a reduced accuracy, if the ball was hit for the current pitch.

Advanced Trajectory & Physics

pfxx
The horizontal (left-right) movement of the pitch during the last 40 feet before the front of home plate, as compared to a theoretical pitch thrown at the same speed with no spin-induced movement. Note: Unlike the Horizontal Break number above, this movement is from the batter's perspective, meaning positive numbers break toward the 1B side, while negative numbers break to the 3B side, for the current pitch.
pfxz
The vertical (up-down) movement of the pitch during the last 40 feet before the front of home plate, as compared to a theoretical pitch thrown at the same speed with no spin-induced movement, for the current pitch.
x0
The horizontal (left-right) location of the pitch 50 feet before the front of home plate. Positive numbers are toward the 1B side, while negative numbers are toward the 3B side, relative to a straight line drawn from the tip of home plate to the center of the rubber, for the current pitch.
y0
The distance from home plate, along a straight line drawn from the tip of home plate to the center of the rubber, 50 feet before the front of home plate. By definition this will always be 50 feet, for the current pitch.
z0
The height of the pitch, relative to home plate, 50 feet before the front of home plate, for the current pitch.
vx0
The velocity (speed) of the pitch in the left-right direction, 50 feet before the front of home plate, for the current pitch.
vy0
The velocity (speed) of the pitch in the direction toward home plate, 50 feet before the front of home plate, for the current pitch.
vz0
The velocity (speed) of the pitch in the up-down direction, 50 feet before the front of home plate, for the current pitch.
ax0
The acceleration (how much speed is changing) of the pitch in the left-right direction, 50 feet before the front of home plate, for the current pitch.
ay0
The acceleration (how much speed is changing) of the pitch in the direction toward home plate, 50 feet before the front of home plate, for the current pitch.
az0
The acceleration (how much speed is changing) of the pitch in the up-down direction, 50 feet before the front of home plate, for the current pitch.

Game & Environment Information

HomeTeam
The name of the home team.
AwayTeam
The name of the away team.
Stadium
The name of the stadium.
Level
The name of the play level, such as for College uses Level (NCAA, Spring, Fall, CCBL, D1, D2, D3), for Minor Leagues uses Level (Rookie, RK, DSL, ShortSeasonA, A, LowA, HighA, A+, AA, Double-A, AAA), for Major League uses Level (MLB, ML).
League
The name of the league.
GameID
The game ID of the current game.
PositionAt110X
The x coordinate of the distance forward (in feet) that a batted ball travels before it lands, or would have landed if it were not caught or obstructed at a 110 foot distance away from home plate, if the ball was hit for the current pitch.
PositionAt110Y
The y coordinate of the height of a batted ball (in feet) when it crosses the plane of 110 feet away from home plate horizontally, if the ball was hit for the current pitch.
PositionAt110Z
The z coordinate of the left-right position (in feet) when it crosses the plane of 110 feet away from home plate horizontally, if the ball was hit for the current pitch.