During a Monday appearance on NFL Network's Up to the Minute program, Del Rio admitted the Raiders received "good value" out of the deal. And he has a good point when considering the Bears sent first-round draft picks in 2019 and 2020, a third-rounder in 2020 and a 2019 sixth-rounder in exchange for Mack and a 2020 second-round pick and a conditional 2020 fifth-round selection.
"It's incumbent on [Raiders general manager] Mike Mayock to turn that draft capital into something really good that can play and get after the quarterback," Del Rio said. "And so, we'll find out. The draft is coming up.
"We're going to find out if they can parlay those picks into something special, but they clearly decided not to pay one of the great human beings and great football players that I've ever coached."
Del Rio coached Mack from 2015 to 2017, a three-season stretch during which Mack totaled 36.5 sacks en route to being named the 2016 NFL Defensive Player of the Year, garnered two All-Pro selections and was named to three Pro Bowls.
Oakland's decision under current head coach Jon Gruden to move on from Mack last year certainly took a majority of observers around the league by surprise, and it appears Del Rio should be included in the group.