Reference

Glossary & Metrics Guide

This glossary explains the core metrics and report components used across Mithrandir Metrics, so first-time visitors can understand what each report is trying to show.

Glossary Section

Pitching Metrics

Stuff

Stuff measures the physical quality of a pitcher’s arsenal. It centers on velocity, movement, extension, and whiff ability rather than just the final line.

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Command

Command tracks how well a pitcher controls the zone and the edges around it. Strike rate, chase rate, edge rate, and CSW% help show whether a pitcher was actually dictating plate appearances.

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Deception

Deception looks at how well pitches play off each other. Tunnel score, pitch-pair separation, and release consistency help explain why hitters may have had trouble identifying the ball early.

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Contact Quality

Contact Quality captures the kind of contact a pitcher allowed. Hard-hit rate, barrel rate, exit velocity, and xwOBA help separate loud contact from weakly hit balls.

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Usage Shift

Usage Shift compares that game’s pitch mix to the pitcher’s baseline mix. It highlights when a pitcher leaned more heavily on one pitch or de-emphasized another.

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Pitch Shape

Pitch Shape visualizes horizontal and induced vertical break by pitch type. It shows how each pitch moves relative to the others in the arsenal.

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Location

The location panel plots where pitches crossed the plate relative to the strike zone. It helps connect command, chase generation, and contact outcomes to pitch placement.

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Tunnel Score / Tunnel Quality

Tunnel quality is a custom deception readout that rewards pitches that begin similarly but finish differently. Higher scores suggest a pitch pair played well together out of the hand.

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Glossary Section

Hitting Metrics

Plate Discipline

Plate discipline captures the hitter’s swing decisions. Chase rate, zone swing rate, contact rate, and whiff rate help show whether the hitter controlled the plate appearance.

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Contact Quality

Hitter contact quality focuses on how dangerous the contact was. Exit velocity, hard-hit rate, barrel rate, and xwOBA help show whether the hitter drove the ball with authority.

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Production / Value

Production / Value summarizes what the hitter actually created in the game. It includes events like walks, total bases, on-base value, and run-value-style production.

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Batted Ball

Batted-ball metrics describe the hitter’s launch profile. Launch angle, sweet-spot rate, and groundball or flyball mix help show what kind of contact the swing produced.

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Hitter Score

Hitter Score is Mithrandir Metrics’ blended single-game grade for hitters. It combines discipline, contact quality, production, and batted-ball shape into one public-facing summary number.

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Swing Decision Map

The Swing Decision Map plots every pitch the hitter saw and classifies it as attack, pass, chase, or discipline. It is designed to show game-level approach at a glance.

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Damage Zones

Damage Zones is a historical location heat map showing where the hitter typically does the most offensive damage. It gives context for whether the day’s swing decisions matched the hitter’s strengths.

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Glossary Section

ABS Metrics

Overturn Rate

Overturn rate is the share of challenges that changed the original call. It is the quickest single measure of how successful challenges were on a given day.

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Batter Challenges

Batter challenges are reviews initiated from the offensive side. They usually reflect hitters trying to overturn called strikes.

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Defense Challenges

Defense challenges are reviews initiated from the fielding side. In practice, these often involve a pitcher or catcher trying to overturn called balls.

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Original Call: Ball

This count tracks how many ABS challenges began as called balls. It helps separate which kinds of calls were being contested most often.

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Original Call: Strike

This count tracks how many ABS challenges began as called strikes. Comparing it with called-ball challenges helps explain the shape of the day’s ABS activity.

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Daily ABS Report

The Daily ABS Report is a league-wide card summarizing challenge volume, success, and location. It is meant to explain how active the challenge system was on a given slate.

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Glossary Section

Running Game Metrics

Attempts

Attempts are all recorded stolen-base tries, whether successful or not. They are the foundation of the daily running-game slate.

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Stolen Bases (SB)

SB counts successful steal attempts. It reflects how often runners actually took the extra base.

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Caught Stealing (CS)

CS counts runners thrown out on steal attempts. It is the main defensive counterpoint to stolen bases.

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Success Rate

Success rate is stolen bases divided by total attempts. It shows how efficient runners were on the bases that day.

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Attempts by Base

Attempts by base split the slate into tries for second, third, or home. It shows where most of the running pressure was applied.

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Top Runners

Top Runners highlights the players who generated the most steal attempts on the date. It is meant to show the most active baserunners, not just successful ones.

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Pitchers Most Run On

This section lists pitchers who faced the most steal attempts. It can reflect pitcher time to the plate, game context, or the types of runners they faced.

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Catcher Shutdown Leaders

Catcher Shutdown Leaders highlights catchers tied to the most caught-stealing outs. It gives quick credit for controlling the running game on successful throws.

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Glossary Section

Statcast / Chart Metrics

xwOBA

Expected weighted on-base average. It estimates offensive quality from launch angle, exit velocity, and strikeout/walk context.

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xBA

Expected batting average. It estimates hit probability from batted-ball quality and speed/context signals.

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xSLG

Expected slugging percentage. It estimates extra-base power from batted-ball quality rather than only observed outcomes.

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Hard-hit%

Share of batted balls hit at hard-contact velocity. Higher rates usually indicate more authoritative contact.

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Barrel%

Share of batted balls with the exit velocity and launch-angle combination most associated with extra-base damage.

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Whiff%

Swings and misses divided by swings. It helps describe bat-missing ability for pitchers and contact risk for hitters.

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K%

Strikeouts divided by batters or plate appearances. In Mithrandir percentile strips, 100th percentile always means best in MLB.

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BB%

Walks divided by batters or plate appearances. It captures patience for hitters and free-pass prevention for pitchers.

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Sprint Speed

MLB running-speed metric, typically measured in feet per second on competitive runs.

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OAA

Outs Above Average. A fielding metric estimating how many outs a defender added relative to expectation.

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ERA

Earned run average. Useful scoreboard context, but noisier than defense-adjusted and contact-quality measures.

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FIP

Fielding Independent Pitching. A run-prevention estimator focused on strikeouts, walks, hit batters, and home runs.

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K/9

Strikeouts per nine innings. A familiar pitcher strikeout rate, best read alongside workload and opponent context.

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Swing Path

A bat-tracking view of swing arc and tilt. Mithrandir currently renders aggregate Savant path metrics, not per-swing motion capture.

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Attack Angle

The upward or downward angle of the bat path through the hitting zone, shown from aggregate bat-tracking data.

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Glossary Section

Mithrandir Terms

Palantir

The stable mainline lane. It emphasizes broad priors, explainable baselines, and everyday signal coverage.

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Fangorn

The nonlinear challenger lane. It looks for segmented interactions that the mainline prior may smooth over.

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Valinor

The calibration-focused lane. It asks whether probability shape, tails, and reliability are behaving correctly.

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Three-lane consensus

A row where Palantir, Fangorn, and Valinor are close enough to indicate cross-lane agreement rather than a single-model read.

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Calibration drift

A warning state where a model lane's recent probability calibration degrades enough to require caution or recalibration.

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Percentile strip

A compact trait chart where 100th percentile means best in MLB, including inverted treatment for negative metrics.

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