J.D. Martinez’s defense? What the numbers really say

TruMedia CTO Jeff Stern discusses defensive metrics with the Boston Red Sox' J.D. Martinez and The Boston Globe.

“The 40-minute conversation between Martinez and Stern was illuminating in trying to assess Martinez’s defense on an individual level and in understanding the evolution of modern defensive statistics — and whether those numbers seen by the public are the same as those used by teams or analysts such as the TruMedia team.”