Wednesday, October 05, 2022
Statcast Metric: Escape Velocity
Similar to the recently discussed Best Speed, we have the concept of Escape Velocity. Any batted ball below a certain threshold, which happens to be right close to the Doc Brown approved 88mph, has no distinguishing value. Whether hit at 87 or 77 or 67, the speed of the batted ball doesn't matter. It's too low to be a homerun, and it's not high enough to do anything other than generate a 0.220 batting average. Therefore, 88 mph becomes an Escape Velocity, the point at which damage starts to happen. And the more you go above 88, the more damage. Not only do batted balls start dropping in for hits at a greater pace than a .220 average, but we also get more homeruns hit at the higher speeds.
Here we can see how it looks for hit and HR rates (be mindful of the differing y-axis scale). Click to embiggen:
While to explain the plays in question, the damage starts happening at 91+ mph, to explain the talent of the players in question, we are interested in how much speed they can generate above 88 mph.
So, what we are tracking is "average speed above Escape Velocity". Any speed below 88 mph counts as 0. If you hit a batted ball at 98, that will count as +10, or 10 mph above Escape Velocity. A batted ball at 108 is +20, and 118 is +30 and so on. We simply average all our speeds above Escape Velocity (and remember, counting as 0 anything below) to get the average speed above Escape Velocity. Look for this on Savant shortly.