Statcast is a state-of-the-art tracking technology that allows for the collection and analysis of a massive amount of baseball data, in ways that were never possible in the past. Statcast can be considered the next step in the evolution of how we consume and think about the sport of baseball that began over a decade ago, when Major League Baseball Advanced Media installed pitch tracking hardware in each Major League stadium. That was a step that unlocked a new age of baseball fandom, and Statcast builds upon that innovation by measuring everything the previous system did, along with a great deal more. It was installed in all 30 parks in 2015 after a partial trial run in 2014.
From 2015-19, Statcast consisted of a combination of camera and radar systems. That changed in 2020, with the arrival of Hawk-Eye. A camera system previously known for powering the instant replay system in professional tennis, among other things, Hawk-Eye offers increased tracking ability as well as a host of exciting new features.
Each club now has 12 Hawk-Eye cameras arrayed around its ballpark. Five of those, which have higher frames-per-second rates, focus on pitch tracking. The other seven are dedicated to tracking players and batted balls. This more robust system has raised the percentage of batted balls that get tracked from roughly 89% to 99%.
Statcast is tracking and quantifying much of the action on the field. That applies to pitching (velocity, spin rate and direction, movement), hitting (exit velocity, launch angle, batted ball distance), running (sprint speed, base-to-base times) and fielding (arm strength, catch probability, catcher pop time). While those numbers are collected on a play-by-play level, they also become the basis for stats that measure players across seasons, such as hard-hit rate for batters or Outs Above Average for fielders.
These metrics allow front offices, broadcasters and fans alike to quantify the raw skills of players in ways that were previously available only to scouts or not available at all. Even in a 2020 regular season shortened to 60 games by the pandemic, more than 260,000 pitches and 43,000 batted balls were tracked. Meanwhile, terms such as "spin rate" and "launch angle" have become ubiquitous not just on broadcasts, but also on ballpark video boards and even on the field, as players across the league use the data and the thinking behind it to elevate their games.
Statcast currently reports measurements (raw numbers from the on-field action) and metrics (combinations of raw measurements into useful numbers).
• Arm Strength: How hard, in miles per hour, a fielder throws the ball.
• Base-to-base Time: How much time, in seconds, it takes a runner to get from one base to another, like Home To First.
• Distance Covered: How far, in feet, a fielder or runner has traveled on a play.
• Extension: How far off the mound, in feet, a pitcher releases the pitch.
• Exit Velocity: How fast, in miles per hour, a ball was hit by a batter.
• Launch Angle: How high, in degrees, a ball was hit by a batter.
• Lead Distance: How far, in feet, a runner is ranging off the bag at the time of a pitcher's first movement or pitch release.
• Pitch Velocity: How hard, in miles per hour, a pitch is thrown.
• Pop Time: How quickly, in seconds, a catcher can get the ball out of his glove and to the base on a stolen base or pickoff attempt.
• Spin Rate: How much spin, in revolutions per minute, a pitch was thrown with.
• Barrels: A batted ball with the perfect combination of exit velocity and launch angle, or the most high-value batted balls. (A barrel has a minimum Expected Batting Average of .500 and Expected Slugging Percentage of 1.500.)
• Catch Probability: The likelihood, in percent, that an outfielder will be able to make a catch on an individual batted ball. Catch Probability accounts for distance needed, time available, direction, and proximity to the wall, compared to how often the same opportunity is caught by Major League outfielders. This allows Statcast to get past the eye test and say "that ball gets caught 95 percent of the time," for example.
• Expected Batting Average (xBA): xBA measures the likelihood that a batted ball will become a hit. Each batted ball is assigned an xBA based on how often comparable balls -- in terms of exit velocity, launch angle and, on certain types of batted balls, Sprint Speed -- have become hits since Statcast was implemented Major League wide in 2015. By comparing expected numbers to real-world outcomes over a period of time, it can be possible to identify which hitters (or pitchers) are over- or under-performing their demonstrated skill.
• Expected Weighted On-base Average (xwOBA): xwOBA is formulated using exit velocity, launch angle and, on certain types of batted balls, Sprint Speed. In the same way that each batted ball is assigned an xBA, every batted ball is given a single, double, triple and home run probability based on the results of comparable batted balls since Statcast was implemented Major League wide in 2015. xwOBA also factors in real-world walk and strikeout numbers, and is reported on the wOBA scale. By comparing expected numbers to real-world outcomes over a period of time, it can be possible to identify which hitters (or pitchers) are over- or under-performing their demonstrated skill.
• Outs Above Average (OAA): A range-based metric of skill that shows how many outs a player has saved over his peers. Prior to 2020, OAA was an outfield-only metric. But it has been expanded to include infielders. OAA is calculated differently for outfielders and infielders.
• Sprint Speed: A measurement of a player's top running speed, expressed in "feet per second in a player's fastest one-second window." This can be delivered on individual plays or as a season average, found by finding all qualified runs (currently defined as anything two bases or more, excluding homers) and averaging the top half of those. In 2017, Buxton led the Majors with a Sprint Speed of 30.2 ft/sec, while the Major League average was 27 ft/sec.
BaseballSavant.MLB.com is MLB.com's clearinghouse for Statcast data. That includes the Savant Illustrator tool for making custom graphics, pre-made leaderboards for top level metrics like Sprint Speed, Outs Above Average and Pop Time, as well as a powerful search tool that allows users to create their own custom queries.
For example, a user could seek to find which batters hit the most opposite-field home runs in 2020. (The answer is DJ LeMahieu, with seven). They could look to see how the percentage of plays featuring an infield shift increased across MLB from 2017 to ‘20. And they could wonder which pitchers got the most swinging strikes on four-seam fastballs thrown in the strike zone and find that in 2020 it was Lance Lynn, with 70. There's a near-endless combination of questions that can be answered using Baseball Savant's public-facing search tool.
The following are all of the terms defined within this section: