In 2016, the Buffalo Bills top four cornerbacks were Stephon Gilmore, Ronald Darby, Nickell Robey-Coleman, and Corey White, with Kevon Seymour slotted as the fifth man. In 2017, none of those five men played a single snap for the Bills.
This is but one example of how volatile the NFL can be, as players, coaches, and executives come and go at a breakneck pace. In 2017, the Bills’ secondary was thought to be a weakness entering the season, but it became arguably the team’s strongest unit on either side of the ball.