GREEN BAY – Psycho, NASCAR, Okie, Big Okie, Sooner, hippo, quad, nickel, dime, dime-plus and dollar. Oh, and Nitro. Don’t forget about Nitro.

As the years pass and offenses evolve, the Packers’ defense and coordinator Dom Capers never stop experimenting with new looks and formations to keep opponents on their toes.

The Packers’ latest innovation – the “Nitro” nickel package – is a sum of the whole, the culmination of more than four years of planning, adjusting and reacting to the direction the NFL’s top offenses are trending.

The personnel – three safeties, three cornerbacks, three linebackers and two defensive linemen – is a reflection of football in 2017. Sturdy enough to defend the run but quick enough to cover. It’s a package built for every season.

The NFL is changing and the value of fast, versatile defenders has never been higher. Hybrid players are in vogue, “tweener” defenders not only willing to step up to the run, but also capable of covering whatever downfield threats emerge.

After installing the package last year, offseason film review showed Capers and his staff it had a future in his defense, and Nitro’s presence could be felt in the Packers’ 17-9 win over the Seattle Seahawks in last Sunday’s regular-season opener.

“We obviously spent the offseason looking at the better offenses and tried to adapt and adjust our defense to what we think we’ll give us the best chance of matching up,” Capers said.

The origin of the Packers’ hybrid package could be traced to 2014 when Head Coach Mike McCarthy and Capers began talking about creating a defense that could help defend against athletic tight ends and multi-faceted running backs.

The first draft was the “quad,” a 4-3 alignment seen as a defense that could defend the run and maximize the athleticism and versatility of Clay Matthews.

Green Bay test-drove the defense for a month before transitioning to more of a nickel concept after the team’s Week 9 bye. Instead of lining up Matthews as a pseudo-slot defender, the Packers moved him into inside linebacker in sub-packages and the defense surged.

Matthews stayed inside for the better part of the next year until the Packers put him back at his natural outside position entering the 2016 season. In Matthews’ stead, Green Bay installed veteran safety Morgan Burnett.

A two-time playoff captain, Burnett blossomed in the new role. Already known as a hard-nosed run defender for his position, the 6-foot-1, 208-pound safety embraced the opportunity to range closer to the line of scrimmage.

“He’s always been a stud playing in the box, but he can also play in coverage,” Matthews said. “Now with where the league is going with tight ends getting more athletic and running backs out of the backfield not just a last resort – anytime you can add more speed and versatility to the field and have matchup problems, I think it benefits you.”

While Burnett powers the package as its resident rover, the maturation of former undrafted free agent Kentrell Brice next to Ha Ha Clinton-Dix is what allows Nitro to work.

Burnett had a career year splitting his time at both spots last season. Along with his team-high 93 tackles, Burnett was one of only two safeties with at least three sacks and two interceptions.

McCarthy hinted this offseason at expanding Burnett’s role and those plans were realized last Sunday against the Seahawks.

Capers deployed Nitro on more than 80 percent of the defensive snaps. The Packers’ ability to defend the run out of the package – 50 yards on 16 designed carries – allowed Capers to stick with it in any situation, including one series where the defense was backed up to its own 3-yard line.

Seattle settled for three field goals in the loss, while its passing game managed only 135 total yards. The Packers had their traditional nickel defense on their ready list, but rode the hot hand with their hybrid package.

“We were prepared to go either way,” safeties coach Darren Perry said. “It’s one of those deals where we’re going to start out with this, but you have to be flexible with it to where you need to make a change and get some bigger bodies in there, we can do that, as well. We started with it and it was going well, and Dom stuck with it.”

The advent of Nitro continues to blur the lines between the Packers’ sub-packages. The biggest difference between Nitro and dime is the personnel the Packers use on their line and who lines up next to Burnett at inside linebacker.

Second-year linebacker Blake Martinez received the call next to Burnett in Nitro against Seattle, with Jake Ryan joining Burnett for one series. Joe Thomas played next to Burnett exclusively in dime.

The defense has put more on Burnett’s shoulders as the key communicator relaying calls, but it’s a responsibility he’s handled seamlessly. Burnett’s years spent leading the safeties helped the veteran forge instant chemistry with Green Bay’s linebackers.

“I think just having a guy out there who has so many years in the NFL and the experience he has, he’s helped me a ton being able to see certain things,” Martinez said. “During TV timeouts, we talk back and forth on certain things, on the sideline we talk through things. It was really good.”

The Packers have flexibility with the package. According to assistant linebackers coach Scott McCurley, all three of Green Bay’s inside linebackers can slide in next to Burnett depending on what the game plan calls for.

While last Sunday was a good start, Capers quickly points out it was only one game. On the eve of this Sunday’s matchup in Atlanta, the veteran coordinator says it’ll take another week of studying and adaptation to properly defend against the Falcons’ speed.

As Green Bay’s defense puts more on film, everyone understands opposing offenses will adjust their concepts and calls accordingly. That’s the cat-and-mouse game Capers has been playing for over 30 years.

It’s also what has enabled his brand of football to endure. Capers hasn’t shied away from thinking outside the box, whether it’s creating a package with only linebackers rushing the passer or finding hidden value in what was once considered one of the league’s most underrated positions.

Over the past two years, however, the Packers have unlocked the potential of their safeties.

“I think it’s a testament to his coaching prowess,” Matthews said. “You look at the great coaches in the league and they’re able to adapt different schemes around certain players. That’s no different here. We’re able to take guys who play different positions and move them around a little bit and figure out what works best for the defense. That’s kind of what we’ve done over the years.”