You may have heard that MLB’s Statcast added something new over the weekend: it now has bat-tracking data. There are a bunch of general overviews of what you can learn from this data, so find those if you’re looking for heavy detail, but I’ll just give you the basics. The data tracks things like how fast a player swings the bat, measured in miles per hour, and how long their swing is, measured in feet. (The league-average bat speed is 71.5 mph*, and Statcast considers anything over 75 as a “fast swing.” Average swing length is 7.