Dan Campbell hired Duce Staley last year as the Lions' assistant head coach, with the goal of grooming Staley into a head coach in the NFL. But the next head coach on Campbell's staff is likely defensive coordinator Aaron Glenn.
Glenn, 49, interviewed for the Jets head coaching vacancy last year and for the Saints head coaching vacancy this year. In a league with just two Black head coaches and five minority head coaches total, Glenn is the "new leader in the Black coach pack," per Peter King of NBC Sports. It's only a matter of time before he lands a job.

In his weekly Football Morning in America column, King said he asked three NFL general managers at last week's combine about Black head coaching candidates, and they all pointed to Glenn. That would seem to indicate that Glenn has overtaken longtime Chiefs offensive coordinator Eric Bieniemy, among others, as the NFL's top Black head coaching candidate.
Saints GM Mickey Loomis told King that Glenn had a 'great' interview with the team earlier this offseason, but New Orleans had a natural head coach in waiting in longtime defensive coordinator Dennis Allen. Per King, "Someone was going to (have to) overwhelm the Saints to knock out Allen. Glenn came close."
“Aaron will be a head coach in our league,” Loomis said.
A three-time Pro Bowl cornerback over a 15-year playing career, Glenn came with Campbell to Detroit last offseason after five years as a defensive backs coach for the Saints. He made an instant impact on the Lions' undermanned defense, even if the final numbers didn't show it. Asked last month about his head coaching prospects, Glenn said, "Whenever my time comes, it comes."
"I think we all know that at some time in my career, that's what I want to do. But I've said this before and I'll say it again: I want to be the best defensive coordinator the Detroit Lions ever had," Glenn said. "Also, I look forward to that day I become a head coach."
King described Glenn as a "steely, bright guy who players (I'm told) love playing for." That's pretty spot-on. Take it from free agent safety Tracy Walker, who revived his career last season in Glenn's defense and has said Detroit's player-friendly coaching staff is a big reason why he wants to return.
"These coaches, they believe in the players," Walker said at the end of the season. "They understand what it’s like to be a player, first off, so they’re open ears. Sometimes we might not be right as players, but they’re still open to hear it. That’s the biggest thing for me. That was the biggest difference (from Detroit's prior coaching staff), honestly. I respect these coaches for that, giving me a voice and hearing me out, regardless if I’m right or wrong."
Campbell seems to know that the clock is clicking on Glenn's time in Detroit. He admitted last month he was "nervous" about losing Glenn to the Saints, and it sounds like he nearly did.
"He would be a great fit," Campbell said at the time. "And honestly, A.G. would be a great fit for just about anybody. That’s how much I think of him and know where he’s going."