Launch Angle represents the vertical angle at which the ball leaves a player's bat after being struck. Average Launch Angle (aLA) is calculated by dividing the sum of all Launch Angles by all Batted Ball Events.
As a guideline, here are the Launch Angles for different types of contact:
- Ground ball: Less than 10 degrees
- Line drive: 10-25 degrees
- Fly ball: 25-50 degrees
- Pop up: Greater than 50 degrees
Hitters can be evaluated by their average Launch Angle, but the tool is generally more valuable in discussing pitchers. In the case of pitchers, the statistic is referred to as "average Launch Angle Against" (aLAA), and it does a good job of telling us what type of pitcher is on the mound. Is he a fly-ball pitcher? Is he a ground-ball pitcher? Average Launch Angle Against attempts to answer those questions.
Generally, pitchers who can limit their Launch Angle Against (keeping the ball on the ground) are more successful, because they are the most adept at avoiding home runs and extra-base hits, which come almost exclusively via fly balls and line drives.
Average Launch Angle tells us about the tendencies of hitters, too -- with a high average Launch Angle indicating a fly-ball hitter, and a low average Launch Angle indicating a ground-ball hitter. On average, fly-ball hitters generally drive in more runs than ground-ball hitters.
In A Call
"The ball left his bat at a X degree angle"