When Major League Baseball’s Statcast system captures a ball in flight, it does more than record a simple play; it generates a cascade of numbers that paint a detailed picture of what just happened on the field.
The New Language of the Game
One of the most talked‑about concepts is the definition of a hard‑hit ball, which Statcast designates as any contact registering an exit velocity of 95 mph or higher. That threshold separates casual contact from the kind of impact that often leads to extra‑base hits.
Closely related is the notion of an optimal launch angle, a window between eight and 32 degrees where a batted ball is most likely to travel far without sacrificing trajectory.
From those raw measurements flow derived statistics such as xBA, the expected batting average that estimates a player’s hit probability based on exit velocity and launch angle, and xwOBA, which layers sprint speed into the equation.
Another useful metric, EV50, captures the average exit velocity of a batter’s hardest half of balls or a pitcher’s softest half, offering a quick snapshot of a hitter’s power or a pitcher’s control.
Bat speed, measured at the bat’s sweet spot, is another indicator of potential power; the league average hovers around the top 90 percent of a player’s swings, and a fast swing is generally defined as 75 mph or more.
The vertical angle of that sweet spot’s travel, often described as the attack angle, helps identify when a hitter is aiming for an Ideal Attack Angle of 5‑20 degrees, a range that correlates strongly with line drives and extra‑base hits.
Beyond hitting, Statcast evaluates fielding with metrics like Jump, which highlights players who react fastest and take the most direct routes in the outfield, and Bolt, which flags any run where a runner’s sprint speed reaches at least 30 ft/sec.
Finally, xERA translates xwOBA onto the familiar ERA scale, giving fans a way to compare pitchers using a single, intuitive number that reflects both quality of contact and speed.