By Zach Koons The veteran defensive back gets a fresh start in Pittsburgh. The Commanders and Steelers are finalizing a trade for William Jackson III that will send the veteran cornerback to Pittsburgh in exchange for draft compensation, as first reported by NFL Network’s Ian Rapoport. It remains unclear exactly which picks Washington will receive in return, but NFL Network’s Tom Pelissero reports that the teams are expected to swap late-round future picks in the deal. Jackson hasn’t played for the Commanders since Week 5, and Rapoport reports that both sides were seeking a fresh start. The 30…