Statcast

About Statcast

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 nearly 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.

At its heart, Statcast is a combination of two different tracking systems -- a Trackman Doppler radar and high definition Chyron Hego cameras. The radar, installed in each ballpark in an elevated position behind home plate, is responsible for tracking everything related to the baseball at 20,000 frames per second. This radar captures pitch speed, spin rate, pitch movement, exit velocity, launch angle, batted ball distance, arm strength, and more.

Separately, each ballpark also has a Chyron Hego camera system, where six stereoscopic cameras are installed in two banks of three cameras apiece down the foul line. The camera system tracks the movement of the people on the field, which allows for the measurement of player speed, distance, direction, and more on every play.

Combined, the radar and camera systems create Statcast, which allows 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. In the first three seasons of Statcast (2015-17), over 2.1 million pitches and nearly 400,000 balls in play were tracked, and terms like "spin rate" and "launch angle" became ubiquitous not just on broadcasts but from the players on the field as well, most notably from players like Daniel Murphy who used the data and the thinking behind it to elevate their game. Nine out of 10 batted balls are directly tracked, with pop-ups and weak grounders being the most susceptible to going untracked. The exit velocity and launch angle of those which are untracked are later estimated using a process developed by MLBAM's Tom Tango.

Available Data

Statcast currently reports measurements (raw numbers from the on-field action) and metrics (combinations of raw measurements into useful numbers).

Measurements include:

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.

Metrics include:

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 takes the individual Hit Probability numbers from each batted ball and reports them on an accumulated seasonal basis, on the batting average scale. By comparing expected numbers to real-world outcomes, 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 takes the individual Hit Probability numbers from each batted ball and reports them on an accumulated seasonal basis, on the wOBA scale. By comparing expected numbers to real-world outcomes, it can be possible to identify which hitters (or pitchers) are over- or under-performing their demonstrated skill.

Hit Probability: The likelihood, in percent, that a batted ball will become a hit, based on exit velocity and launch angle. This removes the effects of defense and ballpark, which the hitter cannot control, and gets to the skill of batted ball contact.

Outs Above Average (OAA): A range-based measure of skill that combines each individual Catch Probability play into an accumulated season-long number which expresses the outcome of the difficulty and frequency of the plays an outfielder has made (or not). In 2017, Byron Buxton led the Majors with +25 Outs Above Average.

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.

Baseball Savant

BaseballSavant.MLB.com is MLB.com's clearinghouse for Statcast data. That includes 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 had the highest average exit velocity against curveballs in 2017, with a minimum of 25 curveballs put in play. (The answer is Aaron Judge, at 97.7 mph.) They could look to see which team's center fielders had the deepest average starting depth from home plate on the road, which in 2017 would have been the Red Sox, at 329 feet. They could wonder which pitchers got the most swinging strikes on sliders thrown above 90 mph, and find that in 2017 it was Chris Archer, with 99. There's a near-endless combination of questions that can be answered using Baseball Savant's public-facing search tool.

In addition, Baseball Savant provides a real-time game feed for any game played in a Statcast-enabled ballpark, and offers an interactive 3D pitch-tracking system.

The following are all of the terms defined within this section: