At the end of the 2014 season, Ken Rosenthal reported that the Rays instructed Drew Smyly to increase the number of high fastballs he throws in an effort to strike more hitters out. A few months later, Jeff Sullivan furthered this story, showing that the Rays have a history of acquiring pitchers with high vertical movement measurements on their fastballs as well as coaching their pitchers to throw their fastballs toward the top of the strike zone.
This organizational philosophy held true in 2015—the Rays' high fastball percentage (20.91%) was most in the league this season.