Elway, the team's executive vice president of football operations, said the Broncos don't know what Fox's team involvement will be during his absence. Elway said the team had been aware Fox would need a procedure "at some point in time."
"The docs are going to tell us the right thing to do," Elway said. "Concern is with John's health, not just this season but the rest of his life."
Elway said defensive coordinator Jack Del Rio was an "easy choice" to serve as interim coach in Fox's absence. Elway spoke with Indianapolis Colts general manager Ryan Grigson on Sunday to "get a feel for what they went through" when Bruce Arians stepped in for Chuck Pagano last season.
"There were a couple options on our staff, but I think that Jack was the one," Elway said. "Discussing with John, we both felt that Jack was the guy who could take the reins over and continue to take us on the path we were on."
Del Rio took the podium after Elway. He wished Fox well and explained he'd continue to serve as defensive coordinator in addition to his expanded duties as interim coach.
"We're on a mission to carry on and continue the things that coach Fox has instilled and started with this football team," Del Rio said. "This is coach Fox's team; I'm merely the person that's able to keep it running right now while he's healing. And I'm very honored to be in this position."