They spent most of that first week together, Dan Campbell and Aaron Glenn, the new Detroit Lions coach and his good friend, defensive coordinator and first hire.
Upstairs in the Lions’ Allen Park headquarters,
“in the lab” on a whiteboard in Glenn’s office, Campbell and Glenn sketched out their vision for the Lions. What kind of players they wanted. How they would coach. What their identity would be as a team.
For four years, Campbell and Glenn worked to bring that vision to life. They stood by each other in tough times. They led the Lions to the NFC championship game. They set a franchise record with 15 regular season wins. And then Glenn left to become head coach of the New York Jets in what Campbell called “one of the greatest days of my life … and one of the worst days of my life.”

“Because you know you're losing a little piece of you,” Campbell said. “That's what he meant to me and to us.”
Glenn, the Lions' defensive coordinator in 2021-24, returns to Ford Field on Sunday, Sept. 27, in his second season with a Jets team that has a familiar look and feel.
At 1-1, the Jets appear to be trending up after an ugly 3-14 season that wasn’t unlike the 3-13-1 one the Lions went through in Campbell and Glenn’s first year together in Detroit.
The Jets play a tough, physical style of football predicated on creating turnovers and running the ball, and they have an emerging young pass rusher in David Bailey and a group of talented offensive skill players – receiver Garrett Wilson, running back Breece Hall, tight end Kenyon Sadiq − in the prime of their careers.
“When I’m looking at them I’m like, ‘This is [bleeping] Lions football, bro. This is crazy,’” Lions defensive tackle Alim McNeill said. “And it’s wild to see because I feel like I’m a part of history a little bit because of this coaching tree, because now you got [former Lions offensive coordinator] Ben [Johnson] over there [as Chicago Bears coach] and then when I watch them I’m like, ‘This is our offense. Like, what the [bleep]?’ And then I’m watching AG and I’m like, ‘This is our defense.’ And … a couple people left with Ben, and a couple people went with AG, so I’m just like, ‘This is so weird.’”
Glenn has four ex-Lions assistants on staff in defensive coordinator Brian Duker, outside linebackers coach Cam Davis, offensive line coach Steve Heiden and pass-game coordinator Seth Ryan, plus receivers coach Shawn Jefferson, who was an assistant with the Lions under Jim Schwartz.
Players reminisced this week about doing 40 up-downs as part of Glenn’s annual rite of passage into his defense, with Glenn in his two knee sleeves dropping to the ground and doing them, too. They recalled how Glenn buried the tape of a particularly poor defensive performance against the Philadelphia Eagles in his first year as DC, when the Lions allowed 236 yards rushing in a 44-6 loss. And they extolled the virtues of his leadership style and how genuinely he cared about his players.
McNeill bought Heiden’s house when Heiden left for New York and worked closely with Davis in Detroit, but it’s Glenn whose return is conjuring up similar emotions to what the Lions went through when Johnson came back for the first time as Bears coach last year.
“I remember when I first came back from being with the Cardinals my second year, I got claimed back here [on waivers] and we were going on an away trip,” linebacker Trevor Nowaske said. “I think it was like one of the first games that I came back that I suited up and played. I think I was inactive the first couple games, and so genuinely he was just talking to me about how he was so happy I was back and how I was going to be a big part of development and stuff like that.
“And I think for me, I needed to hear that as a young person. I think my first probably year, year and a half, kind of had that imposter syndrome of like, ‘Oh, [shoot], hey, do I belong?’ And to have him, the defensive coordinator, say that to me, I still remember to this day it really boosted my confidence.”

For as loved as Glenn was by his players and still is by Campbell − “AG means the world to me. He's one of my dearest friends because I know what he's made of,” Campbell said − there’s also a healthy sense of wanting to kick his and his team’s butt in his return.
It’s a sign of respect in the NFL and something that cuts both ways.
Glenn and Campbell played one season together with the Dallas Cowboys in 2005, spent five years as assistants on the same staff with the New Orleans Saints and went to the same college a couple years apart at Texas A&M.
Asked about playing his old team in a news conference this week, Glenn called Campbell a “really good friend, really good person” and said Detroit is “a place that I coached, a place that I have fond memories, a place that we want to win.”
“It’s the name of the sport; that’s just how it is,” Lions linebacker Derrick Barnes said. “I mean, obviously we've got a lot of respect for AG and he has a lot of respect for us, but at the end of the day, on Sunday, we’re enemies.”
Last year, the Lions handed their friend-turned-enemy Johnson a 52-21 beatdown and his worst loss as Bears coach in his first visit to Detroit, and McNeill said he wants to experience the defensive equivalent against the Jets.
“We need the same thing, and then shut them down, don’t let them score at all,” he said. “And AG, that’ll have him hot. We've got to get him hot after the game. We’ll be friends later. But we've got to do the same thing, we've got to put it on them. And, most importantly for us, to win the game.”
At 1-1, the Lions are off to a disappointing start even if their record is what most expected.
They beat the Saints in overtime in Week 1 and lost to the Buffalo Bills last week on short rest, and they have given up 10 touchdowns in their last 14 non-kneel-down defensive possessions and rank 31st in the NFL in total, scoring and passing defense.
Campbell brushed off suggestions this is a get-right game for the Lions, who are near-touchdown favorites against a team that hasn’t had a winning record in 11 years.
He knows Glenn too well to think this will be anything other than “a knockout, 60-minute brawl,” and he knows how well Glenn knows the Lions, too.
“One of the greatest teammates, people you could ever be around,” Campbell said. “You could talk to him about anything, family, friends, situation, football. We'd all be together and, man, we're laughing, locker room, you go out, getting ready for practice and all of a sudden, it goes on. You put your hands on him now, and it goes from zero to a hundred like this. It’s on. There's no, 'Let's work our way into this.' It's, 'Get your hands off of me.' And so that's what this is a little bit like, man. We are dear, close friends, but we're competing. He wants to win, we want to win. And until that game's over, that’s the way the game is played.”
Dave Birkett covers the Lions for the Detroit Free Press. Contact him at dbirkett@freepress.com. Follow him on Bluesky, X and Instagram at @davebirkett.
This article originally appeared on Detroit Free Press: Lions still love ex-DC Aaron Glenn, but 'on Sunday, we're enemies'








