‘Juiced’ or ‘unjuiced’ baseballs

But various scientific and journalistic studies last year — as well as the anecdotal evidence provided by Justin Verlander and others — found changes to the composition of the baseball itself were responsible, at least in part, for the surge in home runs. And given this season’s drop, speculation has begun that another change to the ball has swung the pendulum back. This season, MLB mandated that all teams store their baseballs in airconditioned rooms, while the Arizona Diamondbacks for the first time are using a humidor at Chase Field to store theirs. Both measures were intended to standardize the baseballs’ “coefficient of restitution,” or, their liveliness. The Diamondbacks’ humidor has served its purpose, as the home run rate at Chase Field has dropped acutely, from 3.5 per cent of all plate appearances in 2017 to 2.7 so far this season. Perhaps the air-conditioned storage across the game is having a similar, if smaller, effect.

Alan Nathan, professor emeritus of physics at the University of Illinois and a leading expert on the physics of baseball, is among those who caution against jumping to any conclusions, about either home run rates or the composition of the baseball.

This year’s decline in homers “might be due to the unusually cold weather,” Nathan said in an email, adding “I am generally skeptical of claims that the ball has changed, whether ‘juiced’ or ‘unjuiced.’ ”

Today’s version of baseball is increasingly an allor-nothing proposition in which, in 2017, more than a third of plate appearances (33.5 per cent) resulted in either a walk, a strikeout or a homer, the highest rate of “three true outcomes” and the lowest rate of balls in play in history.

The problem comes when the recipe for all-or-nothing baseball becomes too heavy on the nothing, and too light on the all.