Entering the 2015 season, Nathan Eovaldi's goal was simple: develop an off-speed pitch. His brief foray into throwing a circle change in Miami was a disaster, so he worked with Larry Rothschild to develop a splitter instead. For the first part of the season, that pitch looked more like a forkball, staying around the mid 80's with very little spin. Then, as his velocity charts show, he tweaked that pitch into a true splitter, with a spike in velo in June:
Since June 26, Eovaldi was a force in the Yankees rotation, with an ERA of 3.