GREEN BAY, Wis. -- Green Bay is Exhibit A in an NFL trend that emphasizes mesmerizing passing games above all else, and Aaron Rodgers nearly passed the Packers to an undefeated season in 2011.
The San Francisco 49ers bucked that trend last year, winning primarily with defense and running back Frank Gore -- and they made it farther than the Packers in the playoffs.
And while both teams spent the off-season trying to become more well-rounded, neither is expected to stray too far from their identity in Sunday's season opener at Lambeau Field (3:25 p.m., FOX).
"Obviously, what they like to do is grind the ball out, grind away in the trenches, and they're really good at that," Packers wide receiver Greg Jennings said. "And they try to eliminate that on the opposing side. What we do is we spread 'em out and we throw the ball around -- and we have fun doing it."
All that fun didn't get the Packers back to the Super Bowl, so they tried to fix their porous defense with draft picks and beef up their running game with the addition of former Bear Cedric Benson.
The 49ers added a few new pieces to their passing game -- including old Packers nemesis Randy Moss.
Those tweaks add intrigue to a pair of potential Super Bowl contenders, but aren't likely to change either team's basic approach.
"Everybody has a formula or team identity they try to play to," Packers coach Mike McCarthy said. "I thought the 49ers did a very good job playing to their identity. Obviously, their success reflected that and I think they continued that through the preseason. Their preseason tape has been very good. We're preparing for their style of play."
Still, the addition of veteran wideouts Moss and Mario Manningham, along with the selection of Illinois wide receiver A.J. Jenkins in the first round of the draft, at least opens up the possibility that the 49ers will make more big plays.
Moss is 35 and was out of football last season, but 49ers quarterback Alex Smith says there's no doubt in his mind that Moss remains a dangerous player.
"A guy like Randy and the unique toolset that he has creates a lot of problems," Smith said. "I think it gives them a lot to think about."
And while Packers fans surely haven't forgotten Moss' heyday with the Minnesota Vikings -- including his notorious fake-mooning episode at Lambeau Field -- McCarthy is more concerned about what Moss can do now.
"I really haven't seen him this preseason so I don't have a strong opinion on where he is today," McCarthy said. "He's a unique talent and you definitely have to be aware when he's on the field."
While Smith was best known for avoiding mistakes last season -- he threw only 5 interceptions in 445 attempts -- he's talking about the possibility that the offense could take a step forward this season.
"We just have so many weapons," Smith said. "So much of this game comes down to matchups sometimes. We have a lot of guys that can do a lot of unique things. I think that's a good problem to have. The more matchup problems you can create the better."
Smith and Rodgers are forever linked by the 2005 NFL draft; the 49ers took Smith with the first overall pick, while Rodgers fell to the Packers at No. 24. That hasn't stopped the two from becoming friends off the field.
And Rodgers said it would be dangerous to discount Smith's potential to make big plays.
"He's a great guy, and a guy who's playing at a high level," Rodgers said. "To have that many pass attempts like he did last year, and then to take care of the football the way he did, didn't get enough credit for the job that he did. That's very difficult to do. And they gave him some weapons this year, and he's going to be a big-time quarterback."
But despite their high-profile additions, Packers defensive lineman Ryan Pickett expects the 49ers to remain a run-first offense.
"They're kind of old-school football," Pickett said. "It is kind of rare. It's not normal to face a team like this. You may face one or two teams like this the whole year. And they do it (well)."
And as one of the Packers' primary run stuffers, Pickett says he's up for the challenge.
"I love that challenge," Pickett said. "I wish every game was like this, honestly."
Rodgers is the reigning NFL MVP, and has perhaps the league's deepest group of wide receivers and tight ends at his disposal. But Rodgers has spent part of the preseason talking about the value of an improved running game, led by Benson.
And Rodgers knows he's in for a tough test against the 49ers defense.
"They've got a lot of talent, a lot of Pro Bowl players, a lot of guys that could be Pro Bowl players," Rodgers said. "Justin Smith is kind of the guy that makes it go at times. He's a blue-collar guy, doesn't always get the stats, but everybody knows how important he is to that team. He's one of the very best players in the NFL, regardless of position. You surround him with a lot of experience, some youth that's playing well, and the guys on the back end are playing well also."