This article is part of our The Saber's Edge series.
At some point during spring training, I planned on writing about how preseason velocities compared to the regular-season values. What I didn't know was Major League Baseball would change their velocity baseline, thereby increasing all the new readings.
The change is important to understand. Once understanding the change, I could calculate how much pitchers maintained their velocity from spring training to the regular season.
I have reported spring training fastball velocity changes for years. Velocity stabilizes almost immediately, with a 1 mph drop equaling a ~0.25 increasein ERA. With this fast stabilization rate, velocity is an early season stat owners can utilize.
At the regular season's start, FanGraph's Dave Cameron wrote about pitchers throwing harder. Almost immediately, MLB Advanced Media's Tom Tango posted an article about the adjustments needed to correct fastball velocities.
The new values reported would be calculated at 55 feet from home plate instead of 50 feet. This difference worked out to a 107 percent increase (~0.6 mph on 90 mph pitch) compared to previously reported values.
With the change, fantasy owners need to put into perspective historical and current fastball speeds. I think most websites will eventually bump up previous values to match up with current values sometime this season or during the next offseason. The current reporting system isn't going to revert back to the slower values, so it's time to embrace the abrupt change. The confusion level will be high this season as everyone adjusts.
Once 2018 begins, the