Sign In
  • Support FanGraphs
    FanGraphs Membership
    FanGraphs Shirts
    FanGraphs Mugs
    Gift a Membership
    Donate to FanGraphs
  • Games
    Ottoneu Fantasy Baseball
    Signup, FAQ, Blog Posts
  • Blogs
    Blog Roll

    FanGraphs
    Podcasts: FanGraphs Audio | Effectively Wild | Chin Music

    FanGraphs Prospects

    RotoGraphs
    Podcasts: The Sleeper and The Bust | Field of Streams | Beat the Shift

    Community Research

    Archived Blogs: The Hardball Times | NotGraphs | TechGraphs | FanGraphs+
    Archived THT: THT Live | Dispatch | Fantasy | ShysterBall
    Archived Podcasts: Stealing Home | Doing It For Bartolo | OttoGraphs | UMP: The Untitled McDongenhagen Project
  • Projections
    2023 Pre-Season Projections
    ZiPS, ZiPS DC
    Steamer
    Depth Charts
    ATC
    THE BAT, THE BAT X
    2023 600 PA / 200 IP Projections
    Steamer600
    2023 Updated In-Season Projections
    ZiPS (RoS), ZiPS (Update)
    Steamer (RoS), Steamer (Update)
    Depth Charts (RoS)
    THE BAT (RoS), THE BAT X (RoS)
    3 Year Projections
    ZiPS 2024, ZiPS 2025
    On-Pace Leaders
    Every Game Played, Games Played %
    Auction Calculator
  • Scores
    Today
    Live Scoreboard, Probable Pitchers
    Live Daily Leaderboards
    Win Probability & Box Scores
    2022, 2021, 2020, 2019, 2018, 2017...
  • Standings
    2022 Projected Standings
    2022 Playoff Odds, Playoff Odds Graphs
    ZiPS Postseason Game-By-Game Odds
    AL East
    AL Central
    AL West
    NL East
    NL Central
    NL West
  • Leaders
    Major League Leaders
    Batting: 2022, 2021, 2020, 2019, 2018, Career
    Pitching: 2022, 2021, 2020, 2019, 2018, Career
    Fielding: 2022, 2021, 2020, 2019, 2018, Career
    Splits Leaderboards
    Season Stat Grid
    60-Game Span Leaderboards (Special)

    KBO Leaders
    Batting, Pitching

    Minor League Leaders
    AAA: Triple-A East, Triple-A West, Mexican
    AA: Double-A Northeast, Double-A South, Double-A Central
    A+: High-A Central, High-A East, High-A West
    A: Low-A West, Low-A East, Low-A Southeast
    R: Appalachian, Gulf Coast, Pioneer, Arizona
    R: Dominican
    WAR Tools
    Combined WAR Leaderboards
    WAR Graphs
    WPA Tools
    WPA Inquirer
    Rookie Leaders
    Batters 2022, Pitchers 2022
    Splits Leaders
    Batters: vs L, vs R, Home, Away
    Pitchers: vs L , vs R, Home, Away
  • Teams
    Team Batting Stats
    2022, 2021, 2020, 2019, 2018, 2017...
    Team Pitching Stats
    2022, 2021, 2020, 2019, 2018, 2017...
    Team WAR Totals (RoS)
    AL East
    Blue Jays  |  DC
    Orioles  |  DC
    Rays  |  DC
    Red Sox  |  DC
    Yankees  |  DC
    AL Central
    Guardians  |  DC
    Royals  |  DC
    Tigers  |  DC
    Twins  |  DC
    White Sox  |  DC
    AL West
    Angels  |  DC
    Astros  |  DC
    Athletics  |  DC
    Mariners  |  DC
    Rangers  |  DC
    NL East
    Braves  |  DC
    Marlins  |  DC
    Mets  |  DC
    Nationals  |  DC
    Phillies  |  DC
    NL Central
    Brewers  |  DC
    Cardinals  |  DC
    Cubs  |  DC
    Pirates  |  DC
    Reds  |  DC
    NL West
    D-backs  |  DC
    Dodgers  |  DC
    Giants  |  DC
    Padres  |  DC
    Rockies  |  DC
    Positional Depth Charts
    Batters: C, 1B, 2B, SS, 3B, LF, CF, RF, DH
    Pitchers: SP, RP
  • RosterResource
    Current Depth Charts
    AL East
    Blue Jays
    Orioles
    Rays
    Red Sox
    Yankees
    AL Central
    Guardians
    Royals
    Tigers
    Twins
    White Sox
    AL West
    Angels
    Astros
    Athletics
    Mariners
    Rangers
    NL East
    Braves
    Marlins
    Mets
    Nationals
    Phillies
    NL Central
    Brewers
    Cardinals
    Cubs
    Pirates
    Reds
    NL West
    D-backs
    Dodgers
    Giants
    Padres
    Rockies
    Offseason Tools
    2023 Opening Day Tracker
    2023 Offseason Tracker
    2023 Free Agent Tracker
    In-Season Tools
    2023 Closer Depth Chart
    2023 Injury Report
    2022 Lineup Tracker
    2023 Payroll Pages
    2022 Probables Grid
    2022 Schedule Grid
    2023 Transaction Tracker
  • Prospects
    Prospects Home
    THE BOARD!
    THE BOARD: Scouting + Stats!
    How To Use THE BOARD: A Tutorial
    Top Prospects List
    Top Prospects
    2023 2022
    AL
    BALCHWHOU
    BOSCLELAA
    NYYDETOAK
    TBRKCRSEA
    TORMINTEX
    NL
    ATLCHCARI
    MIACINCOL
    NYMMILLAD
    PHIPITSDP
    WSNSTLSFG
    AL
    BALCHWHOU
    BOSCLELAA
    NYYDETOAK
    TBRKCRSEA
    TORMINTEX
    NL
    ATLCHCARI
    MIACINCOL
    NYMMILLAD
    PHIPITSDP
    WSNSTLSFG

    • 2022 Preseason Top 100

  • Glossary
    Library
    Batting Stats
    wOBA, wRC+, ISO, K% & BB%, more...
    Pitching Stats
    FIP, xFIP, BABIP, K/9 & BB/9, more...
    Defensive Stats
    UZR Primer, DRS, FSR, TZ & TZL, more...
    More
    WAR, UBR Primer, WPA, LI, Clutch
    Guts!
    Seasonal Constants
    Park Factors
    Park Factors by Handedness
  • Sign In
Help Support FanGraphs


Become a Member No Thanks
Already a member? Log In
  • Intro
  • Features
  • Offense
    • Complete List (Offense)
    • OBP
    • OPS and OPS+
    • wOBA
    • wRC and wRC+
    • wRAA
    • Off
    • BsR
    • UBR
    • wSB
    • wGDP
    • BABIP
    • ISO
    • HR/FB
    • Spd
    • Pull%/Cent%/Oppo%
    • Soft%/Med%/Hard%
    • GB%, LD%, FB%
    • K% and BB%
    • Plate Discipline (O-Swing%, Z-Swing%, etc.)
    • Pitch Type Linear Weights
    • Pace
  • Defense
    • Overview
    • Def
    • UZR
    • DRS
    • Defensive Runs Saved – 2020 Update
    • Inside Edge Fielding
    • Catcher Defense
    • FSR
    • RZR
    • TZ / TZL
  • Pitching
    • Complete List (Pitching)
    • ERA
    • WHIP
    • FIP
    • xFIP
    • SIERA
    • Strikeout and Walk Rates
    • Pull%/Cent%/Oppo%
    • Soft%/Med%/Hard%
    • GB%, LD%, FB%
    • BABIP
    • HR/FB
    • LOB%
    • Pitch Type Linear Weights
    • SD / MD
    • ERA- / FIP- / xFIP-
    • Plate Discipline (O-Swing%, Z-Swing%, etc.)
    • Pace
    • PITCHF/x
      • What is PITCHF/x?
      • Pitch Type Abbreviations & Classifications
      • Heat Maps
      • Common Mistakes
      • PITCHf/x Resources
  • WE/RE/LI
    • RE24
    • Win Expectancy
    • WPA
    • LI
    • WPA/LI
    • Clutch
  • Principles
    • DIPS
    • Regression toward the Mean
    • Replacement Level
    • Sample Size
    • Splits
    • Projection Systems
    • Linear Weights
    • Counting vs. Rate Statistics
    • Park Factors
    • Park Factors – 5 Year Regressed
    • Positional Adjustment
    • Aging Curve
    • League Equivalencies
    • Pythagorean Win-Loss
    • Luck
  • WAR
    • What is WAR?
    • WAR for Position Players
    • WAR for Pitchers
    • FDP
    • fWAR, rWAR, and WARP
    • WAR Misconceptions
  • Business

UZR

by Piper Slowinski
February 15, 2010

Ultimate Zone Rating (UZR) is one of the most widely used, publicly available defensive statistics. UZR puts a run value to defense, attempting to quantify how many runs a player saved or gave up through their fielding prowess (or lack thereof). There are a couple different components to UZR, including:

● Outfield Arm Runs (ARM) – The amount of runs above average an outfielder saves with their arm by preventing runners from advancing.
● Double-Play Runs (DPR) – The amount of runs above average an infielder is by turning double-plays.
● Range Runs  (RngR) – Is the player an Ozzie Smith or an Adam Dunn? Do they get to more balls than average or not?
● Error Runs (ErrR) – Does the player commit more or fewer errors compared with a league-average player at their position?

The run values in each of these categories are then compiled into one overall defensive score, UZR. Since UZR is measured in runs, it can be compared easily with a player’s offensive contributions (wRAA or similar statistics). While there are other defensive metrics available, FanGraphs uses UZR in its WAR calculations for non-catchers. You may also see UZR/150 around the site, which is simply UZR scaled to an average number of chances for a season.

Calculation:

For the details on how UZR is calculated — i.e. how we can attach a run value to defensive events — see the FanGraphs UZR Primer. It’s very thorough. The specifics can be a little overwhelming, but at it’s most basic level, it’s a measure of the average amount of damage that batted ball would do and how often it is converted into an out, relative to average at the position. So if the average left fielder makes a player 40% of the time on the ball in question and that batted ball (based on location, speed, etc) is worth 0.8 runs on average, fielding it cleanly earns you 0.48 runs toward your UZR (0.8*0.6). It’s a little more nuanced than that, but that’s the view from 30,000 feet.

Why UZR:

This isn’t the right place to debate UZR versus another similar metric, but you should use a metric like UZR or DRS because it is a better representation of defensive value than something like fielding percentage. Even your eyes aren’t going to do a great job measuring defensive performance because you simply can’t watch and remember enough plays a year to have a good sense of exactly how well a player stacks up against the competition. You might be able to judge a single play better than the metrics (although that’s debatable), but your ability to recall every play and compare them is limited. Run value defensive stats like UZR provide you with the best estimate of defensive value currently available  and allow you to estimate how much a player’s defense has helped his team win.

How To Use UZR:

UZR is as easy to read as it is difficult to calculate. UZR tells you how many runs better or worse that player has been relative to the average player at his position. A +5 UZR at third means the player is five runs better than the average third baseman.

There are some reasons for caution, however. First, UZR is relative to positional average so you want to factor in the fact hat some positions are harder to play than others. For that reason we have the positional adjustment, which we add to UZR to get DEF.

The other thing to remember is that UZR isn’t going to work well in small sample sizes, especially a couple of months or less. Once you get to one and three-year samples, it’s a relatively solid metric but defensive itself is quite variable so you need a good amount of data for the metrics to become particularly useful. There’s plenty more to say about this issue, but that’s for another entry. In general, UZR isn’t perfect because it doesn’t factor in shifts, positioning, and can’t perfectly measure everything it needs to, but it’s still among the best options out there.

Context:

Defensive statistics should not be taken as 100% accurate, just like anything. There are plenty of reasons why they might not be telling you a complete story, and the Overview section goes into a lot of detail about that. As far as interpreting UZR, if you’ve gotten to that point, the scores can be broken down into the following tiers. This is a good shorthand way of evaluating a player’s defensive ability level:

Defensive Ability UZR
Gold Glove Caliber +15
Great +10
Above Average +5
Average  0
Below Average -5
Poor -10
Awful -15

Things to Remember:

● Beware of sample sizes! If a player only spent 50 innings at a position last season, it’d be a good idea not to draw too many conclusions from their UZR score over that time. Like with any defensive statistic, you should always use three years of UZR data before trying to draw any conclusions on the true talent level of a fielder.

● UZR uses Baseball Info Solutions (BIS) data in calculating its results. It’s important to note that this data is compiled by human scorers, which means that it likely includes some human error. Until StatCast data gets released to the public, we are never going to have wholly accurate defensive data; human error is impossible to avoid when recording fielding locations by hand, no matter how meticulous the scorers. That said, BIS data is still the best, most accurate defensive data available at this time, so just be careful not to overstate claims of a player’s defensive prowess based solely on defensive stats.

● Since UZR is a counting statistic like RBIs or HRs, the more playing time a player accrues, the higher (or lower) their UZR will be. In order to compare players with different amounts of playing time, UZR can be  scaled on a 150 game basis (UZR/150). If you want to compare a player with 90 games played to someone with 140, UZR/150 would be the way to do so.

● UZR is park-adjusted, meaning it adjusts for the fact that fielders have to deal with odd quirks in certain ballparks.

Links for Further Reading:

Intro to UZR – Big League Stew

The Mike Silva Chronicles: UZR – The Book Blog

Similarities and Differences: UZR and Dewan +/-

Background to UZR, Pt. 1 – Baseball Think Factory

Background to UZR, Pt. 2 – Baseball Think Factory





xFIP
 
DRS

Piper was the editor-in-chief of DRaysBay and the keeper of the FanGraphs Library.

Login
Please login to comment
8 Comments
Oldest
Newest Most Voted
Inline Feedbacks
View all comments
Kyle Hmember
11 years ago

Wait why would dividing UZR by 150 even things out? shouldn’t you divide it by the number of games they played and then multiply by 150? Or is UZR/150 just the name of the statistic

1
Piper Slowinski
11 years ago
Reply to  Kyle H

Good question. Instead of thinking of it as UZR divided by 150 (because it’s not that simple), consider it as UZR per 150 games.

3
CamraMaan
11 years ago

I know this is a year old post, but just in case someone reads this, how come Jose Lopez has a UZR of 8.1 and a UZR/150 of 7.5 at 3B in 2010? He played in 150 games that year, albeit Yahoo says he DH’d in eight games, and played 3B in 142. Still, if this is a counting stat, shouldn’t his UZR/150 be higher…? I have to assume its not as simple as UZR divided by games played at the position, multiplied by 150…?

2
tonny
11 years ago

gostaria de revender como faco

0
Robert Lotter
11 years ago

Information Report. Was’t a few was probably particularly trying to get when My husband and i dug into Msn your site showed up i found out not to mention i thought i’d as a minimum many thanks.

-1
Rabbit
11 years ago

Still has a long way to go. For example, anyone who has seen A. Cabrera play knows he is one of the best defensive shortstops in the AL. Yet he is ranked dead last. Suzuki is also very underrated.

-2
shamus
11 years ago

I’ve had the same question as CamraMaan; is UZR/150 actually scaled to 150 games played or some amount of innings, like 1350? I’ve tried to figure it out both ways and it never seemed like UZR/150 was based on 150 games or 1350 innings of a player’s production.

I’m assuming Kincaid’s explain is correct here: http://www.fangraphs.com/forums/topic.php?id=3256 ?

0
caseyhudson
3 years ago

The “number of runs” NOT “the amount of runs”.

-2
You are going to send email to

Move Comment

Updated: Saturday, January 28, 2023 7:05 AM ETUpdated: 1/28/2023 7:05 AM ET
Player Linker - @fangraphs - Contact Us - Advertise - Terms of Service - Privacy Policy
sis_logo
All major league baseball data including pitch type, velocity, batted ball location, and play-by-play data provided by Sports Info Solutions.
mlb logo
Major League and Minor League Baseball data provided by Major League Baseball.
Mitchel Lichtman
All UZR (ultimate zone rating) calculations are provided courtesy of Mitchel Lichtman.
TangoTiger.com
All Win Expectancy, Leverage Index, Run Expectancy, and Fans Scouting Report data licenced from TangoTiger.com
Retrosheet.org
Play-by-play data prior to 2002 was obtained free of charge from and is copyrighted by Retrosheet.