"I missed the camaraderie of the room, the interaction with the staff, the interaction with the players," Pettine said. "The chess-game part of it – the designing a game plan tailored to your opponent. (Being a head coach is) the furthest thing from my mind. I'm here to coordinate an outstanding defense and win a Super Bowl."

Working as a consultant, Pettine had a chance to study Green Bay's defense a little last season and sees a cupboard that's anything but bare of talented personnel.

After recently getting a chance to meet Clay Matthews for the first time, Pettine said he looks forward to maximizing the six-time Pro Bowl linebacker's versatility and building around the defense's talented nucleus of Mike Daniels, Kenny Clark and Ha Ha Clinton-Dix.

When asked the type of defense fans can expect from his unit, Pettine says he likes his scheme to be multiple yet simplistic. His defenses have been known to use both 3-4 and 4-3 concepts, though the widespread evolution of spread offenses has increased the deployment of nickel and dime sub-packages.

In his five seasons in New York and Buffalo, Pettine's defenses never finished outside the top 10 in total yards. He accomplished that by stressing details and fundamentals. He wants his players to play with an aggressive mindset and believes his scheme has adapted to be successful in the NFL's current CBA environment, which limits player-coach offseason contact.

"I always want our guys to know that scheme is worthless unless you play with great passion and great technique," Pettine said. "I know people have said the system can be very complicated. We like to appear multiple without necessarily putting that much stuff in. So, it's not a system that is overwhelming to learn."

Head Coach Mike McCarthy said he jotted down five "clear components and characteristics" he was looking for during his search for a defensive coordinator.

While he praised in-house candidate Joe Whitt Jr. for his "outstanding" performance in the interview, McCarthy said Pettine "knocked it out of the park" and proved to be the "right man for the job" in the end.

McCarthy is looking for Pettine to spark a turnaround after injuries and inconsistency hampered the league's 22nd-ranked defense in 2017. After talking with new General Manager Brian Gutekunst, McCarthy believes everyone from the front office down to the coaching staff is rowing in the right direction.

"There's specific areas where we need to improve on defense, starting with the pre-snap," McCarthy said. "We need to do a better job of winning the pre-snap when you get into scheme and so forth. At the end of the day, we have a certain level of experience on defense and we'll try to build off of that. We need to add players to our roster. That's clearly a focus."