With context, it's easy to see where Nick Leddy's recent usage decline came from. The 2017-18 season was a historically bad defensive year for the New York Islanders and Leddy. The 2018-19 season saw the Islanders' defensive depth chart get deeper, and more effective with the implementation of Barry Trotz's defense-first system.
Leddy spent much of 2018-19 adjusting to the Islanders' new Trotz-ian style of play. The system's effects were immediately apparent on the Eden Prairie, Minnesota native, as he saw an incredible +42 differential between 2017-18 and 2018-19 plus-minus ratings, finishing with a flat 0 in 2018-19.