Jack Del Rio, who will return to coach the Jaguars for his ninth season this fall, won't be calling defensive plays. Jacksonville defensive coordinator Mel Tucker will assume those duties and personnel will be changed as well. "We had so many explosive plays allowed this year it's alarming, and it's something we're going to have to give a lot attention to and we're going to have to fix," Del Rio said. " ... We identified the defensive line as an area we needed to strengthen, we did that, and the other part that we knew we had to improve is our secondary. And we'll address that this offseason and get that straightened up."