Cleveland Indians closer Cody Allen is a very good, if pretty conventional, relief pitcher. He throws a curveball instead of a slider, but generally his profile is familiar. He get a lot of strikeouts. He gives fans a heart attack every now and again. And his batted ball profile has a stark outlier in it.
Usually a pitcher gains the reputation of being a groundball or fly ball pitcher. The second is also often tied to being a high strikeout guy, though nothing is permanent in baseball. Over the last three years, though, Allen has shown a very strange fluctuation in his batted ball profile.