To McCarthy, it came down to his team not playing to the identity that had allowed it to qualify for the playoffs in the first place.

So if there’s one key lesson McCarthy is trying to pass along to his players as they return to the Wild Card round on Sunday, this time in Philadelphia, it’s that the Packers must play the game the way that made them a successful 10-6 team over the past four months.

“Just stay true to our own values, stay true to our brand of football,” McCarthy said. “We have just gone through a 16-game season. We are the 2010 Packers. We have a brand of football that we are very confident in, very comfortable with, and that’s what we’re taking to Philadelphia.

“I don’t want anybody to act differently, don’t want anybody to look differently. I want everybody to be the best that they can be being themselves, and that’s for every player, every unit, every phase of our football team.”

The identity of a football team can be a bit of a nebulous concept, but in looking at what went wrong in last year’s playoff loss, McCarthy’s point makes a lot of sense.

The 2009 Packers finished the regular season first in the league in turnover ratio at plus-24, and they had the fewest giveaways in the league with just 16. Yet they turned the ball over twice within their first three offensive snaps, and fell behind 14-0. Then they lost the game on a turnover, as Arizona returned a fumble for a touchdown in overtime.

The 2009 Packers also led the league in rushing defense, yet an Arizona offense not known for running the ball still piled up 156 rushing yards, more than the Packers gave up in any regular-season game. In addition, an offensive line that corrected early-season issues and allowed only 10 sacks over the final seven regular-season games suddenly allowed five sacks in one playoff contest.

Those are just a few examples from a year ago, and it’s those types of deviations from a successful formula that can spell doom in the postseason.

Heading into this year’s playoff game, the Packers’ identity isn’t the same. There are some similarities, but there’s a lot about this team that has changed, too.

For one, unlike last year, the Packers finished this regular season with their backs against the wall, playing the past two weeks needing to win to see their season continue. That alone gives them an approach to draw upon now that the playoffs are here.

“I think it’s just not much changes,” running back John Kuhn said. “If you already had it locked up and maybe you relaxed a couple weeks before you get in, … but we’ve been here having to bust it just to get in. So we kind of know what it’s like to go into this game now. You lose and you’re done. We all got that.”

The defense also possesses some lofty rankings again this year, but in different categories. The Packers finished No. 2 in the league in scoring defense and No. 1 in the NFC at 15.0 points per game, having allowed seven points or fewer five times.

One key to that was a climb from No. 28 in red-zone defense up to No. 12. Opponents last year scored touchdowns on 61 percent of trips inside the 20, compared to 48 percent this year, the defense’s best red-zone percentage since 2003.

That strength will be leaned upon against Philadelphia, a big-play offense that can score from anywhere on the field with quarterback Michael Vick at the helm. If the Packers can make a team take the long way down the field, so to speak, they’ve proven their ability to rise up and eventually get the stop.

“I know it’s tough to have long, sustained drives against our defense,” veteran defensive end Ryan Pickett said. “We’ve been pretty good about getting off the field, especially early in the game, so it’s tough for anybody to drive the ball on us.”

Particularly lately. The defense allowed two big plays for touchdowns in the second quarter in Week 16, but after that it clamped down on two teams with double-digit wins (the Giants and Bears) and allowed only six points over the last six quarters.

“Our defense has been playing real well,” linebacker Clay Matthews said. “I think (the scoring ranking) is a fantastic testament to the coaches and players and what not, and we need to continue that through the playoffs.”

Relentless pressure has played a big part. Led by Matthews with 13½, the Packers finished tied for second in the league with 47 sacks and ranked first in the NFC in sacks per pass play. It won’t be as easy to bring down Vick as it was Chicago’s Jay Cutler six times this past week, of course, but staying after the quarterback will play a major factor in any potential playoff success.

“We’ll keep applying pressure, and that’s the way our team likes to play,” said cornerback Charles Woodson, who continues to be used extensively as a blitzer.

“I like playing an attacking style defense, and I think everybody else on the team, I think it just gets everybody’s juices flowing. It keeps everybody warmed up and revved up and ready to go. That’s what we like to do, and for myself, I love doing it.”

Turnover ratio remains a key statistic for the Packers, though it doesn’t jump off the page as much as last year. Green Bay finished plus-10, good for fourth in the league and second in the NFC to No. 1 seed Atlanta (plus-14), and the offense continued to capitalize on the defense’s takeaways this year, ranking in the top five in points off of turnovers again with 111.

What has changed, and it goes hand-in-hand somewhat with the red-zone defense, is the ability to limit points off of turnovers. The Packers allowed only 39 points (six field goals, three touchdowns) following the offense’s 22 giveaways this season, with the three touchdowns the fewest given up by Green Bay since the statistic began being recorded in 1995.

After allowing 16 giveaways to be converted into 10 touchdowns a year ago, the defense did not allow a touchdown off a turnover until Week 12 this season, and then one of those three TDs on the season was an interception returned for a score. It was a marked improvement in what the coaching staff refers to as “adversity defense,” a focus since last year.

Another season-long emphasis was penalties, and the Packers have made discipline part of their current identity as well. After three straight years among the top five most penalized teams in the league, the Packers set a franchise low (since the NFL went to a 16-game schedule in 1978) with just 78 accepted penalties this season. They ranked tied for third in fewest penalties and third in least penalty yardage (617).

On offense, it’s a little harder to pinpoint identifying marks for a couple of reasons. McCarthy’s system uses many different personnel groupings by design to keep defenses off-balance, and the unit has been far less consistent this year than in the past.

But if there’s one thing that usually equates to success, it’s efficient quarterback play, and Aaron Rodgers has shown he can find that rhythm. Taking out the Detroit game in Week 14 when he played less than a half and left with a concussion (and then missed the subsequent game at New England), Rodgers put together a string of five straight completed games with a passer rating above 114, and four of those were above 130.

The efficiency took a dip this past week against Chicago (89.7), but Rodgers and the offense know what they’re capable of because they’ve executed at a high level much of the second half of the season. Rodgers also knows the errors early and late in last year’s playoff game tarnished his spectacular play in between in setting a franchise playoff record with 423 yards passing.

“Hopefully I’ll play better,” Rodgers said. “You can only do the things you can control, and that’s my preparation, and that’s going to be solid as it usually is. It’s a tough challenge playing a defense like this. They’re a talented group. There’s no margin for error.

“It starts with taking care of the football, and that starts with me because I touch it every play, so I need to take care of the football, hopefully get us in good situations, and if we can have some balance, we’re hopeful we can move the ball a little bit.”

So in summary, the 2010 Packers are a battle-tested, disciplined team with an aggressive defense that keeps them in games and an offense built around efficient quarterback play.

Put that together for four quarters and the Packers are confident they’ll be a tough out in this postseason.

“I think to win in the playoffs, you have to play a 60-minute game,” Rodgers said. “We didn’t do that last year, but this is a different team. New challenges have faced us this season, adversity. But we’ve stuck together and we’re excited that we’re in the playoffs and we get another opportunity.

“We have to play our brand of football. It’s got us to this point. We’re 10-6, into the second part of the season which is the playoffs, and we just need to stick to what we do best.”

Additional coverage - Jan. 5