What Is Ultimate Zone Rating (UZR) in Baseball?

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Fielding is an essential part of baseball, but sometimes the best defenders are overlooked because it is difficult to measure defensive skills. For that reason, baseball analysts have worked to create defensive statistics that accurately capture a player’s value and abilities with the glove. One of the most commonly used defensive metrics is UZR.

UZR stands for Ultimate Zone Rating. It is a defensive statistic that attempts to quantify how many runs a fielder saves or costs his team on defense. A positive UZR means a fielder saved his team more runs than the average player at his position, while a negative UZR means the fielder cost his team more runs than the average defender at his position.

UZR is publicly available on the internet, so it is frequently used by analysts, journalists, fans, and even teams. It is also used by FanGraphs to calculate part of the defensive component of their version of Wins Above Replacement (WAR). All UZR records can be found on the FanGraphs website.

When Was UZR Created?

UZR was created by Michael Litchman of Baseball Think Factory and was first introduced in 2002. All UZR data since 2002 is available online.

How To Use UZR

All players start with a UZR of zero. As they play, their UZR can rise, fall, or remain the same. A good defender’s UZR will go up, a bad defender’s UZR will go down, and a perfectly average defender will remain at zero.

As a general rule of thumb, a good defender might have +5 UZR at the end of the season, and a great defender might have +10 UZR. On the other hand, a bad defender might finish with -5 UZR, while an awful defender could have -10 UZR.

UZR is best used to compare players who play the same position. This is because some positions are more difficult to field than others. For example, a first baseman with a high UZR is not necessarily a better defender than a shortstop with a low UZR, because it is much harder to play shortstop than first base.

It is important to keep in mind that UZR is not meant to be used over a small number of games. Without a large sample size of data, one or two plays can bias the numbers. Therefore, it’s best to look at UZR after a full season.

What Are the Components of UZR?

The components of UZR are Outfield Arm Runs (ARM), Double-Play Runs (DPR), Range Runs (RngR), and Error Runs (ErrR). Infielders are evaluated using DPR, RngR, and ErrR, while outfielders are evaluated using ARM, Rngr, AND ErrR. UZR is not used to evaluate catchers and pitchers.

If you add up an infielder’s DPR, RngR, and ErrR, you will get his total UZR. Similarly, an outfielder’s UZR is the sum total of his ARM, Rngr, and ErrR.

What Is UZR/150?

UZR is a counting statistic, which means a positive UZR will grow higher the more games a fielder plays, and a negative UZR will get lower the more games a fielder plays. Therefore, if a player has a higher UZR than another player at his position, it could mean the first player is a better defender, or it could just mean the first player has played more games.

To compare players with different amounts of playing time, you can use UZR/150. This statistic is simply UZR scaled to 150 games. Therefore, if a player has played exactly 150 games at his position, his UZR and UZR/150 will be the same. If he has played fewer than 150 games, his UZR/150 will be higher than his UZR, and if he has played more than 150 games, his UZR/150 will be lower than his UZR.

Where Can I Find UZR?

UZR is available online at FanGraphs.com, listed under the “Fielding Leaders” tab on their website.

Who Has the Highest UZR in Baseball History?

The player with the highest UZR in baseball history is third baseman Adrián Beltré, who accumulated a UZR of 179.0 in his 21-year career. However, UZR was not introduced until his fifth MLB season. Behind Beltré on the all-time UZR leaderboards are outfielders Ichiro Suzuki, Andruw Jones, and Carl Crawford.

Among active players, shortstop Andrelton Simmons has the highest Ultimate Zone Rating. In eleven MLB seasons (through 2022), he has accrued 114.0 UZR.

Jones holds the record for the highest UZR/150 in his career. In over 17,000 innings in the outfield, Jones has a 17.4 UZR/150. The active player with the highest UZR/150 is Simmons.

Who Has the Most UZR in a Single Season?

The player who holds the record for most UZR in a single season is Alfonso Soriano. He finished with a UZR of 33.2 in 2007, playing left field and a little bit of center. Close behind Soriano is Franklin Gutierrez, who had a UZR of 31.0 playing center field in 2009.

Soriano also holds the record for the highest UZR/150 in a single season (among qualified fielders). His UZR/150 in 2007 was 38.2.

As for teams, the record for most UZR in a season belongs to the 2009 Seattle Mariners. The Mariners had 89 UZR that year, led by Gutierrez in center field.

Who Has the Worst UZR in Baseball History?

The player with the worst UZR in baseball history is Manny Ramirez, who had a career UZR of -117.3. He is one of only two players with a career UZR below -100. However, he played the first nine years of his career before UZR was introduced. Among active players, Jose Altuve of the Houston Astros has the lowest career UZR at -39 and counting.

The player with the worst UZR in a single season is right fielder Brad Hawpe, who had -36.1 UZR in 2008. Hawpe also holds the record for the worst UZR/150 in a season (among qualified players). He had a -44.7 UZR/150 in 2008.

Finally, the team that holds the record for lowest UZR in a season is the 2005 New York Yankees. They had a UZR of -141.7 in 2005. No other team has ever had a UZR below -100.

Why Do Catchers Not Have UZR?

Catchers do not have an Ultimate Zone Rating. This is because the actions a catcher performs on defense are significantly different from the actions all other fielders perform.

UZR measures how well a fielder responds to balls in play, and catchers are rarely tasked with fielding such balls. The most important skills for catchers are pitch framing, controlling the running game, and preventing passed balls. UZR does not measure these skills.