GREEN BAY—Clay Matthews referred to the Packers’ league-worst ranking in run defense as a “wake-up call” and “reality check” on Thursday.

Fellow veteran defensive bookend Julius Peppers then put the Packers’ need to shore up that area in the most basic of perspectives.

“We don’t have a choice,” Peppers said.

With the second half of their schedule beginning Sunday night against the archrival Bears, if the Packers are going to make a run at their fourth straight NFC North title, the defense cannot continue hemorrhaging yards on the ground.

The Packers have given up more than 190 rushing yards in a game three times this year, including a season-worst 235 in the first meeting with the Bears six weeks ago. Matt Forte had 122 of them. That’s the game that plummeted the Packers to last in the league rankings, and that’s where they’ve stayed.

The solution commonly offered when a run defense leaks is for players to stay gap sound, to know where they fit in the scheme to plug holes.

Head Coach Mike McCarthy made it clear there’s more to it, though.

“When you talk about run defense, everybody talks about the fit, make sure you’re fitting in the right place,” McCarthy said. “Well, once you fit, you need to whip the man over you and make the tackle. I think sometimes we try to do things a little bit too right.”

McCarthy’s message seems to be getting through. Peppers talked about “attitude” and toughness while Matthews mentioned “swagger.” With the simplest of phrases, safety Micah Hyde called it the ability to “play football.”

However they interpret it, what matters is the knowledge that the fix goes beyond the technical. Simply being in the right place isn’t enough.

“You have to read where the ball is going, see which hole, get off blocks and tackle,” Hyde said, in defining what it means to “play football.”

“That’s what it comes down to. We can get caught up in ‘this guy is supposed to be in the A gap, this guy B …’ It’s all good to say, but when you go out there and you’re reacting, things happen differently.”

Since the first Chicago game, several defenders have mentioned the Packers didn’t adjust to some different looks and blocking schemes the Bears threw at them.

Adjustments appeared to be made over the next three weeks, as the Packers held the Vikings, Dolphins and Panthers to an average of just 110 yards on the ground, but then the Saints rolled up 193 and sent the Packers into their bye on a sour note.

“When we do have lapses, it’s not a few runs here or there, it’s significant yardage,” Matthews said. “That’s what we need to address. We can’t just pick and choose when we’re going to show up and what running backs and what schemes we’re going to shut down.

“With all that being said, we’ve proven we can stop the run. We just have to do it now.”

It will help the defense that three starters appear ready to return from injury. Defensive end Datone Jones (ankle), safety Morgan Burnett (calf) and cornerback Sam Shields (knee) have all been full participants in practice the last two days.

Having the secondary fully healthy for the first time since the first half of the Miami game will be a plus against Chicago receivers Brandon Marshall and Alshon Jeffery. In the first meeting, they each caught a short TD pass, but they were held to a combined six catches for 58 yards, their lowest and second-lowest totals, respectively, in 2014. The pass-catcher who did the most damage was tight end Martellus Bennett, with nine catches for 134 yards.

Matthews has repeatedly referred to this offense as the most dangerous Bears one he’s faced in his career, and the multitude of weapons does have a pick-your-poison quality. Back in Week 4, the noise Bennett made in the passing game while Marshall and Jeffery were quiet speaks to that.

It all comes back to Forte and the run, though. This is the matchup that sent up the red flags on defense, which makes it the perfect time to begin quieting the concerns. As Peppers noted, there’s really no alternative.

“We’re going to get better, we’re going to get tougher, we’re going to get better at stopping the run,” Peppers said, “and it’s going to start this week.”

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