Once upon a time, strikeouts minus walks was the best way to look ahead for a pitcher. It focused on the things that a pitcher could control and left the rest to league averages, and therefore it was a strong ‘one number’ to look at.
We are in the midst of turmoil, though. In the middle of the biggest year to year increase in home run rate, we’re suddenly looking at pitchers with home run problems and wondering which ones will continue to be ridiculously ‘unlucky’ and which ones will shortly conquer their gopher problem. Don’t worry, the pitchers themselves are doing the same thing.
The good news is that we have new tools to help us figure out which home run rates are more likely to regress. The home run is the result of the correct launch angle and the correct velocity. We know that 25-30 is the ideal home run launch angle, but for these purposes, I expanded it to 20-35 to get a broader range. We also know that 95+ mph in those zones leads to home runs, so I included a ranking of exit velocity in that band.