The Packers’ defense had a hard time keeping 49ers quarterback Colin Kaepernick in check, both in last season’s playoffs and in the season opener (above). (Marcio Jose Sanchez/AP)

The tour groups still come through here by the bus load, and one paused Wednesday morning outside the doors to Lambeau Field’s massive atrium, just in front of the statues of Curly Lambeau and Vince Lombardi. A guide spoke over a microphone, regaling the photo-snapping legions with tales of what happened once, long ago, right here to their beloved Green Bay Packers. It was why these people came to an empty football stadium midweek, and they stood, rapt.

Inside, there were more mundane, if more pressing, matters. “I’m not here to talk about what happened,” defensive end B.J. Raji said. “I’m moving on.”

It is a constant struggle here, where the fan base can’t separate itself from the Packers’ past, because the Packers’ past informs their expectations about the present. And currently, as Green Bay prepares to host Washington in its home opener Sunday, that present includes some significant worries, almost all of them on the defensive side of the ball.

The Packers endured an entire offseason of consternation over the 579 yards they yielded to San Francisco in an NFC semifinal playoff loss, then opened the season last Sunday against the 49ers and coughed up 494 more in losing again, 34-28. Only Baltimore, which was flummoxed by Denver’s Peyton Manning, allowed more yards during the NFL’s opening week.

So the questions for the Green Bay defense — questions that were part of the fabric of the 2011 season, when the Packers gave up more yards than any team in the NFL — returned this week in force. Fail to answer them against the Redskins, and they will linger longer, into autumn.

“It doesn’t matter what they say,” defensive end C.J. Wilson said. “We always worry about what we say on the inside, in the locker room. . . . We’re a defense that can do it. Coach told us before the season even started: We have to have an edge, a chip on our shoulder every game. No matter who says what, we’re going to go out there with a chip on our shoulder.”

The message inside the Lambeau locker room Wednesday was clear: Don’t think these Packers are those from two years ago, when they gave up 411.6 yards a game. They should not, either, be defined by their struggles against the 49ers, in which quarterback Colin Kaepernick initially ran past them (181 yards rushing in the playoff game) and then passed over them (412 yards last Sunday). This is a unit that tosses out the evidence and replaces it with confidence.

“We just believe in what we have,” veteran defensive lineman Ryan Pickett said. “We feel like we can be the number one defense in the league. That’s how we approach it.”

Part of that is because Green Bay is now fully transformed into a 3-4 scheme, a change initiated by Coach Mike McCarthy when he hired defensive coordinator Dom Capers before the 2009 season. Part is, too, because of the personnel, particularly in the front seven, where Clay Matthews is a disruptive linebacker and Raji the kind of space-eating lineman needed to anchor a 3-4. McCarthy used Wednesday as an opportunity to put the brakes on any defense-in-disarray talk.

“I thought that the defense’s approach to the last game, as far as the objectives — went out to stop the run, do those types of things — we addressed that,” McCarthy said. “We have to learn from what we did do wrong. But I think this unit’s clearly more in sync than we’ve been in prior years as far as coming out of training camp. I have a lot of confidence.”

But there are, as safety M.D. Jennings put it, “some technical issues” for Green Bay as the Redskins approach. In the offseason, the Packers put in time trying to figure out the read-option offense employed to some degree by both San Francisco and Washington, including a trip by defensive coordinator Dom Capers and his coaches to Texas A&M to pick the mind of Aggies Coach Kevin Sumlin, who has both used and defended the offense at the college level. Though the Packers would open the season against two NFC playoff teams from 2012, led by two of the league’s most dynamic young stars, it provided focus.

“It was kind of a gift,” Raji said. “We don’t really know what Washington’s doing, but going into the season, we’re thinking, ‘Two option teams, get them out of the way Week 1 and Week 2, that’s better than seeing them Week 8 and Week 9.’ We looked at it as a positive.”

The Post Sports Live crew offers bold predictions for the Redskins at the Green Bay Packers on Sunday. (Post Sports Live/The Washington Post)

Then a couple things happened that put a kink in that outlook. In the San Francisco game, Kaepernick showed he didn’t have to run to be successful; only Dallas and Baltimore gave up more passing yards than Green Bay in the opening week. And after the Redskins’ season-opening loss to Philadelphia, in which Washington fell behind 33-7 and had to pass to catch up, there is considerable question about how much quarterback Robert Griffin III will be able to execute the running portion of the offense as he eases his way back from offseason knee surgery.

The Packers, too, are stressed by a hamstring injury to starting safety Morgan Burnett, who sat out against San Francisco, which used tight end Vernon Davis to control the middle of the field against Jennings and Jerron McMillian. Green Bay failed to come up with a turnover.

“We’ve got to make more plays in the passing game,” Capers told reporters here Monday.

One game doesn’t make a defense, nor does it make a franchise. As the tour group listened to the lecture Wednesday morning — “Lombardi left for Washington, and he turned around Washington in one year,” the guide said — the work inside Lambeau Field went on. By Sunday, when the Packers take that field for the first time this year, the temperatures will feel like fall in the Midwest, the season will start in earnest, and the expectations for the beloved Packers — and their defense — will be the same as they always are.