The team hasn't named a replacement for Steve Russ, who became the Carolina Panthers' linebackers coach in January. Russ had spent the previous four seasons as Air Force's defensive coordinator and defensive backfield coach.
Calhoun told ESPN.com on Tuesday that the experience of the defensive staff and its ability to collaborate on play calls and scheme creates little urgency for a designated coordinator.
"I don't know if it's necessarily a delay," the 51-year-old Calhoun told the Colorado Springs Gazette when asked why he has yet to announce his new coordinator. "I've yet to see a law or an edict that says that you must.
"We'll see as we head down the road here. I think the key is I want to make sure fundamentally we are much, much better in terms of open-field tackling, getting off blocks and the clarity of what we're doing defensively with our scheme."
Potential in-house candidates for the position are Tim Cross (assistant head coach, defensive line coach), Ron Vanderlinden (inside linebackers), Brian Knorr (edge defenders), John Rudzinski or Chip Vaughn (secondary) and Matt Weikert (outside linebackers).
Air Force opens the season Sept. 1 against Stony Brook.