GREEN BAY, Wis. – In the summer of 2014, the Green Bay Packers went to great lengths to keep secret a new defensive package they planned to throw at the Seattle Seahawks in the regular-season opener.

They called it “quad” – a 4-3 alignment that, in theory, would provide more run support than Dom Capers’ standard 3-4 front. They practiced it behind closed doors in minicamp and OTA sessions, barred reporters from publicizing it during training camp and didn’t play a single snap of it preseason.

And it bombed.

Capers ditched it early in the year and never called it again.

“Nitro” was this summer’s quad, although without the shroud of secrecy. They practiced openly all summer with safety Morgan Burnett (or rookie Josh Jones) lined up at inside linebacker in their nickel (two defensive linemen, four linebackers) front, and Capers even explained the logic behind it during a news conference last month.

“You’re still going to have your front guys you feel good about playing the run and the pass, [but] it gives you a more athletic group to play with on first and second down,” Capers said.

Lo and behold, it worked just how Capers had hoped in Sunday’s season-opening 17-9 win over the Seahawks. Capers used the “nitro” package, unofficially, on 42 of the 49 defensive snaps and sprinkled in only a few snaps of base 3-4 (what he calls “Okie”) and dime (with six defensive backs in the secondary).

Even with Burnett, a 209-pound safety at middle linebacker (usually next to Blake Martinez), the Packers handled the run just fine.

“I think that was one of the huge reasons why we were able to be in it was we were able to stop the run,” Martinez said.

It also put Burnett in a good position to spy Seahawks quarterback Russell Wilson. Although he was Seattle’s leading rusher (40 yards), he did so on just two runs. The rest of the Seahawks’ rushing totals were 16 carries for 50 yards.

“Nitro” affords an opportunity for hard-hitting safety Kentrell Brice to get on the field next to Ha Ha Clinton-Dix. The three cornerbacks in that package for most of the game were Davon House and Damarious Randall on the outside with Quinten Rollins in the slot. Brice moved into Burnett’s natural spot in the secondary when Burnett played in the box.

But if the Packers couldn’t have handled the run with their smaller lineup, Capers would have been forced to abandon it.

“It just puts more, I don’t want to say more speed, but it allows us to play just faster, at a faster pace,” said Brice, who recorded three tackles in 47 snaps against the Seahawks. “Speed and athleticism. It’s more of a better coverage factor as well. You have a safety covering a tight end or a back rather than a linebacker against a receiving threat.”

Sunday’s game at Atlanta could feature more of the “nitro” package given that it will take as much as speed on the field as possible to keep up with Matt Ryan, Julio Jones and one of the NFL’s potent passing games. In last season's NFC Championship Game against the Packers, Ryan threw for 392 yards – 180 of them to Jones.

Here’s another way the Packers’ defense will look different to the Falcons: They cut cornerback LaDarius Gunter on Tuesday. Last year, Gunter was their No. 1 cornerback in the playoffs, but he fell out of the rotation and was released to make room for receiver Geronimo Allison, who was coming off a one-week suspension.

This much is sure, if Capers does plan to use “nitro” again this week, the Falcons will have plenty of reps to study.

The Packers actually tinkered with it last season, moving Burnett to an inside linebacker spot at times. Capers also has a package called “Sooner” that features a safety at inside linebacker in a base 3-4 scheme.

“Offenses are trying to space you out and get you in personnel that they can mismatch you in,” Martinez said. “And I think us being able to have that package allows us to be able to match up against offenses.”