I read (forget where) that the average fly ball distance has increased about 5 feet since 2015 (or around then). It doesn't sound like much but adds up to a lot. There's apparently scuttlebutt that the seams on the ball are tighter (not as elevated) this year, thus reducing drag in flight. More important than reducing drag in flight is that the lower seams make it harder for the pitchers to grip a breaking ball. And once they throw the ball, the lower seams offer less wind resistance, so they break less. See Bernoulli's principle: https://en.wikipedia.org/wiki/Bernoulli%27s_principle So, its mostly sliders and fastballs and fewer pitches that change the plane of the hitter's swing. (No, I'm not Jay Hook) Later