In 2016, the typical major league plate appearance is more likely to result in a homer than ever before. And this onslaught happened quickly: Home runs on contact—the rate at which non-strikeout at-bats produce dingers — is up 35 percent compared with 2014
So we bought a dozen official “Bud Selig”-branded balls from 2014 and a dozen “Rob Manfred”-branded balls from the second half of 2015, and we sent them to the Sports Science Laboratory at Washington State University. There, they were fired from a high-speed air cannon at a steel plate so that their coefficient of restitution — basically, their bounciness — could be measured precisely. But “Steel-Plategate” didn’t catch on: while the tests did detect a small increase in bounciness, variation between individual balls was so high that the overall change wasn’t statistically significant.
We couldn’t confirm the juiced-ball hypothesis, but we also couldn’t dismiss it.