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When Major League Baseball introduced Statcast cameras to all 30 stadiums in 2015, it was the beginning of a new era in baseball analysis. These devices allowed MLB to measure aspects of the game we could previously only evaluate with the eye test. In particular, Statcast has had a tremendous impact on how we assess defense, thanks to the development of the new defensive metric OAA.
OAA stands for “Outs Above Average.” It is a statistic for measuring a baseball player’s defensive abilities. It is calculated using Statcast data from MLB Advanced Media and is published on Baseball Savant.
Outs Above Average measures how many outs a player has saved for his team compared to an average fielder. In simplest terms, it is calculated by measuring how far a fielder has to move to make a play and how much time the fielder has to move that distance. The best fielders are able to move great distances in short amounts of time. OAA is among the most nuanced and accurate defensive metrics available today.
When Was OAA Created?
Statcast data has been publicly available since the 2015 season for batters and pitchers. Outs Above Average was developed a little later and has been available since 2017. The data dates back to the beginning of the 2016 season.
Before the 2020 season, OAA was only available for outfielders. It is now available for infielders too, dating back to 2016. OAA is not available for catchers or pitchers.
How Does OAA Work?
OAA uses various factors to determine the difficulty of a play. For infielders, this includes how far the fielder has to move to get to the ball, how much time the fielder has to reach the ball, how far the fielder is from where the ball needs to be, and how fast the opposing baserunner can run. For outfielders, OAA also considers the direction in which the fielder needs to move to reach the ball.
Taking all these factors into account, OAA calculates how likely it is that an average fielder could make such a play. If a particular player consistently makes difficult plays, he can expect to have a higher OAA. On the other hand, if a player often fails to make easier plays, his OAA will be on the lower side.
How To Use OAA
All players begin the season with zero OAA. In other words, every player starts at the league-average mark. If a player were to play perfectly average defense all season long, his OAA would remain at zero.
If a fielder plays above-average defense, his OAA will rise throughout the year. If a fielder plays below-average defense, his OAA will fall throughout the year. Therefore, a good defender will have a positive OAA, while a poor defender will have a negative OAA.
It is important to remember that OAA, like all defensive metrics, is best used in large sample sizes. It is a very helpful tool for evaluating a player’s defense over a full season or multiple seasons, but it is not very effective for evaluating a player’s defense over a handful of games. In a small sample size, a couple of good or bad plays can have a huge influence on a player’s OAA.
What Is a Good OAA in Baseball?
As the name suggests, OAA is scaled to league average. Therefore, a player with 0 OAA is considered an average defender. An OAA above zero is better than average, while an OAA below zero is worse than average.
A strong defender might have 4-5 OAA over a full season, while an elite defender would have 8+ OAA. The very best defenders in any given season might have 20+ OAA.
Baseball Savant uses a color gradient to illustrate good OAA scores. A player with a light red OAA is a fine defender according to this metric, while a player with a dark red OAA is an excellent fielder.
What Is a Bad OAA in Baseball?
While a good defender might have 4-5 OAA over a full season, a bad defender might have -4 OAA, while a terrible defender might have -8 OAA. The very worst defenders in a year could have an OAA of -15 (or even lower).
Baseball Savant also uses a color gradient to illustrate bad OAA scores. A player with a light blue OAA is a poor fielder by to this metric, while a player with a dark blue OAA is a dreadful defender.
Where Can I Find OAA Online?
Outs Above Average is available on the MLB Advanced Media website Baseball Savant. OAA leaders can be found under the “Leaderboards” tab, and individual player OAA can be found on each player’s page.
OAA is also available on FanGraphs.com leaderboards and player pages. FanGraphs uses OAA data to calculate part of the defensive component (DEF) of their version of Wins Above Replacement (WAR).
Who Has the Highest OAA in Baseball History?
The player with the highest OAA since the statistic was introduced is shortstop Francisco Lindor. He has accumulated 117 OAA throughout his career with the Cleveland Guardians and New York Mets. Lindor debuted in 2015, while OAA data is available from the 2016 season onwards. Thus, his career OAA could have been even higher if OAA had been developed a year earlier.
Shortstop Nick Ahmed has the second-highest career mark with 105 OAA. As of the 2022-23 offseason, Lindor and Ahmed are the only two players with a career OAA above 100.
The team with the most overall OAA is the Houston Astros. The Astros have 181 OAA since 2016, putting them well ahead of the second-place Chicago Cubs.
Who Has the Most OAA in a Single Season?
Nick Ahmed holds the record for the highest OAA in a single season. In 2018, he amassed 35 OAA playing shortstop for the Arizona Diamondbacks.
In second place is Javier Báez, another shortstop. Báez had 32 OAA for the Cubs in 2019. Ahmed and Báez are the only players ever to record more than 30 OAA in a single season.
The team with the highest OAA in a single season was the 2017 Minnesota Twins. The Twins had 66 OAA that season. No other team has ever surpassed the 60-OAA threshold in a single year.
Who Has the Worst OAA in Baseball History?
The player with the worst career OAA is shortstop Didi Gregorius, who has recorded -76 OAA in his MLB career. He has played for the Diamondbacks, Cincinnati Reds, New York Yankees, and Philadelphia Phillies.
Gregorius is one of only five players with an OAA of -50 or lower in his career. The others are Nick Castellanos (-68), Jonathan Villar (-61), Kyle Schwarber (-52), and Daniel Murphy (-51).
The team with the lowest overall OAA is the Baltimore Orioles. The Orioles have amassed -130 OAA since 2016.
Who Has the Lowest OAA in a Single Season?
In 2016, outfielder Matt Kemp recorded -26 OAA, the worst figure in the history of OAA. Kemp split the 2016 season between the San Diego Padres and Atlanta Braves. He played mostly right field.
Kemp is one of seven players to finish a season with an OAA of -20 or below. The others are Jonathan Villar in 2016 (-22), Brad Miller in 2016 (-22), Nick Castellanos in 2018 (-22), Jorge Polanco in 2019 (-21), Andrew Vaugh in 2022 (-20), and Vladimir Guerrero Jr. in 2019 (-20).
The team with the lowest OAA in a single season was the 2017 New York Mets. The Mets had -57 OAA that year. They were the first team ever to drop below -50 OAA in a single season.
What Is OAA for Pitchers?
OAA for pitchers tells you how the defense performed with a certain pitcher on the mound. In other words, a pitcher’s OAA is the cumulative OAA of every player who was in the field while he was pitching.
OAA for pitchers is available on the Baseball Savant OAA leaderboards. This leaderboard also provides similar OAA data for batters and batting teams.
What is Outfield Directional OAA?
Outfield Directional Outs Above Average splits up a player’s OAA into six categories to reflect that player’s defensive performance in six different directions. The six directions are back, back left, back right, in, in left, and in right. “Back” refers to moving backward, while “in” refers to moving forwards.
A similar version of Directional Outs Above Average is available for infielders. It is split up into four directions: back, in, lateral towards first base, and lateral towards third base.
What Are Other Defensive Metrics in Baseball?
OAA is one of the most commonly used defensive metrics. However, it is not the only one. Other statistics that can be used for a similar purpose are Defensive Runs Saved (DRS), Ultimate Zone Rating (UZR), and Range Defense Added (RDA). All of these stats are considered “advanced defensive metrics” because they are more refined and precise than traditional stats like errors and fielding percentage.