GREEN BAY, Wis. – Rex Ryan thought Mike Pettine was just a video guy, someone who could help him put together film that would keep his Baltimore Ravens players interested and focused on the game plans.

That was 16 years ago, when Ryan was the Ravens' defensive line coach and Pettine worked in the team’s video department.

He quickly discovered that Pettine was much, much more.

“He’s the smartest guy in the room,” Ryan said.

Former Browns head coach Mike Pettine will get the most out of the Packers as their new defensive coordinator, says his former boss Rex Ryan. AP Photo/Aaron Josefczyk

And that comes without a caveat, Ryan said. It doesn’t matter who’s in the room.

“I was trying to spice up my presentations, and the more I talked to him, I realized, ‘Holy cow, this dude knows everything, he’s a real football guy,’” Ryan, now an ESPN analyst, said in an interview Wednesday – one day after the Packers hired Pettine as their new defensive coordinator.

“So when we had the chance, we made him quality control coach, and then outside linebackers and then defensive coordinator. He was my right-hand man forever.”

Ryan took Pettine with him to the New York Jets when he became the head coach in 2009 and made him defensive coordinator. Not a bad rise for a guy who left high school coaching in Pennsylvania, where his dad was a coaching legend, to take a low-paying job with the Ravens in 2002.

From 2009 to 2012, Ryan and Pettine tag-teamed the Jets’ defense that ranked first, third, fifth and eighth. Pettine then left the Jets in 2012, with Ryan’s blessing, to become the Bills' defensive coordinator in 2013. In Pettine's only season in Buffalo under coach Doug Marrone, his defense ranked 10th. So in five seasons as an NFL coordinator, he has been part of five top-10 defenses.

“I know how much I missed him when he moved on,” Ryan said. “When he took the job in Buffalo, it wasn’t that I ever fired Mike Pettine; that wasn’t the case. What happened was we had a new general manager, and we all knew we were going to get fired. So I was like, ‘Hey, Mike, take as many guys as you can with you.’ And he did. He took Jim O’Neil, Anthony Weaver -- a lot of coaches with him.

“Then I’m sitting back going, 'Now it’s just me.'”

A year later, Pettine's meteoric rise culminated with the Browns' head-coaching job. He went 10-22 and was fired after two seasons.

“That record he has in Cleveland looks pretty good now,” Ryan said. “The guy there is going to have to coach 10 years to get that many wins.”

Even when Pettine was out of football in 2016 after he was fired by the Browns, Ryan relied on him to help him with the Bills in an unofficial capacity. Last season, Pettine spent time around the Seattle Seahawks, although he was not officially a member of their staff.

It’s now Pettine’s charge to infuse new ideas into the Packers’ defense that finished 22nd in Dom Capers’ final season and hasn’t been in the top 10 since the Super Bowl season of 2010. Coach Mike McCarthy picked Pettine over three internal candidates -- linebackers coach Winston Moss, safeties coach Darren Perry and cornerbacks coach Joe Whitt.

“He’ll be the best coordinator in the league; that’s how good he is,” Ryan said. “I think the big thing is, the fan base ought to be super excited about him because this is a good get. There’s other names out there or whatever, but this is the best coach out there that they could’ve got."

The Ryan/Pettine defensive system, like Capers’, is rooted in a 3-4, but it has principles from other schemes as well.

“He’s not one of these guys who’s going to play one or two fronts and three coverages,” Ryan said. “This guy is going to give you the gamut. We have a philosophy, and Mike has it, it’s a 'KILL' philosophy -- keep it likable and learnable -- and that’s what we do, and that team is going to play fast and play physical, and I can’t wait to watch them.”

Ryan rejected the idea that it’s too complicated for a young defense, which the Packers often field.

“That’s not true, not at all,” he said. “You’ve just got to be smart in a way that if you love football, then you’ll love playing in this defense. If not, you really shouldn’t be in the league. If you don’t want to play in this system, you don’t want to play in any system.

“It will make good players great. If you’re an average player, you’ll be good. There’s times when Mike and I were together, we literally had no NFL corners, and yet we found a way to make it work. And I think there’s times when we’ve had great players and we’ve had historic success. If you love the game, then these guys died and went to heaven in this system.”