GREEN BAY – The Packers have owned the NFL’s No. 1-ranked rushing defense previously under Mike McCarthy, but the job is getting done differently this year.

Back in 2009, Dom Capers’ first season as defensive coordinator, Green Bay finished the season tops in the league against the run and set a franchise record in the process by allowing just 83.3 rushing yards per game.

This year the Packers are on a historic pace, allowing only 171 yards so far (42.8 avg.). According to the Elias Sports Bureau, that’s the second-fewest rushing yards allowed through four games since the statistic was kept beginning in 1933. San Francisco surrendered 157 yards through four games back in 1995.

It’s still Capers’ same 3-4 scheme as 2009, but then again it isn’t. Unlike seven years ago, the Packers’ base defense now is in essence their nickel with three cornerbacks, because opposing offenses line up so regularly with three wide receivers.

“We’ve probably played far more sub personnel, nickel personnel than we did at that time,” Capers said. “We were more base 3-4 because we were seeing more two-receiver sets.”

That base 3-4 featured three big down linemen in the middle. Johnny Jolly and Cullen Jenkins started every game at the ends, with Ryan Pickett and rookie B.J. Raji sharing time at nose tackle. They’d be flanked by two outside linebackers, Clay Matthews and converted lineman Aaron Kampman (and then rookie Brad Jones after Kampman was lost to a knee injury), with veterans Nick Barnett and A.J. Hawk manning the inside linebacker spots.

Rarely have the Packers put three defensive linemen on the field together this season. The opposing offensive personnel has dictated that, with veterans Mike Daniels and Letroy Guion taking the lion’s share of those first- and second-down snaps.

“We’d line up three guys that were 335, 340 back then,” Capers said. “Where I think (now) we’ve got a little bit more athletic ability, quickness, but people are spreading you out and you need more.”

Guion (322 pounds) and Daniels (310) aren’t small, but the Packers’ biggest lineman, Mike Pennel (332) hasn’t even played yet. The need for only two defensive linemen on a regular basis also has allowed for a deeper rotation, as rookies Kenny Clark, Dean Lowry and Brian Price, along with another young lineman in Christian Ringo, have all taken snaps.

Of that group, only Price has yet to record at least three tackles already, whereas in 2009, outside of the four linemen already mentioned, only two others (Jarius Wynn and Mike Montgomery) recorded two or more tackles all season long.

This year’s outside linebackers also rotate much like the linemen, with Matthews and Nick Perry backed up by Julius Peppers, Datone Jones, Jayrone Elliott and rookie Kyler Fackrell. Seven years ago, only Brandon Chillar (who also played inside linebacker) and Brady Poppinga rotated in behind the starters.

The inside linebacker groups were built differently, too, with veterans Nick Barnett and A.J. Hawk in their seventh and fourth years in the league back then, respectively. This year’s inside linebacker trio of Blake Martinez, Jake Ryan and Joe Thomas has no one further along than year two.

“The growth of our younger players has helped us as far as keeping guys fresh,” McCarthy said this week. “The rotation has really benefited from that. We’re not seeing a real high play count so far, knock on wood, of any of our players.

“The more people you can play, especially when you’re rotating a number of different players on the defensive front, it’s really helpful.”

The similarities between the two units are in the personalities, according to Matthews, the lone member of both defenses. A rookie in ’09, Matthews sensed right away he was joining a tough bunch, and he feels the same about the current group.

“The guys we had, they didn’t take a lot of mess from anybody and you kind of see that with Mike Daniels,” Matthews said. “You can’t have an interview with him without him yelling at you or letting you know how much of a badass he is. The same goes with Letroy.

“You look at the young talent we have in there in Kenny and Dean as well as four, six guys on the edge. It’s so disruptive to offenses when you’re not playing into their hand. I think that’s why we’ve had a lot of success.”

The 2009 unit climbed slowly to its No. 1 ranking. The Packers were 20th against the run after Week 5, climbed into the top five after Week 10, and reached the top spot over the final two games.

This year’s group has held the No. 1 spot from the get-go after allowing Jacksonville just 48 yards on 26 carries in Week 1.

The 2009 defense never faced a test quite like this week, either. The best rushing offenses the Packers battled that year were Baltimore (which finished the season No. 5) and, coincidentally, Dallas (No. 7).

This year’s Cowboys are No. 1 on the ground at 155 yards per game, nearly 20 better than every other team in the league except No. 2 Tennessee. Star rookie Ezekiel Elliott’s 546 rushing yards sit at least 85 yards ahead of everyone else.

It’s a good bet the Packers will play more base defense this week than they have all season, and the right mix of size and quickness in the rotation up front will be paramount against the Cowboys’ vaunted offensive line.

“You still need the guys that can hang in there with a line like this, because this line is a combination of not only size, but they’re very good athletes,” Capers said. “You have to match up the same kind of athletes with them.

“I think they’re confident that they can run the ball no matter what they see. Most really good running teams feel that way, that no matter what you put there, we’re gonna block you.”

The Packers have to, well, avoid getting blocked, at least enough to prevent the Cowboys from controlling the game on the ground.

It’s been the story of the week, and it’s finally time for it to be written, one way or the other.

“It doesn’t take long looking at these guys on tape to know that we’re going to have to be at our best,” Capers said. “They’re the best in the league at running the ball, so sure, it’s a challenge, but I like our guys’ approach and attitude.”