It really all started June 29, 2016, when the Edmonton Oilers dealt All-Star Taylor Hall to the New Jersey Devils for defenseman Adam Larsson, who had barely established himself since being drafted fourth overall in 2011. Oilers general manager Peter Chiarelli was mostly savaged for the trade, which was immediately overshadowed by the blockbuster deal the same day that swapped franchise defensemen P.K. Subban and Shea Weber.
A year later, between Subban and the Nashville Predators' run to the Stanley Cup Final and the Vegas Golden Knights' stockpiling blueliners in the expansion draft, defensemen have never been more valuable.