Where: Lambeau Field, Green Bay, Wis. (grass, outdoors)

When: Sunday, 4:25 p.m. ET (FOX)

Spread: Packers by 5

Forecast: Mostly sunny; projected kickoff temperature: low 70s

2011 records -- Packers (15-1); 49ers (13-3)

Past results: Two most recent meetings -- Dec 5, 2010: Packers 34, 49ers 16; November 22, 2009 -- Packers 30, 49ers 24. Series record: Packers hold a 34-26-1 edge.

What matters: This is offensive firepower -- Green Bay -- against defensive willpower -- 49ers. The Packers were the highest-scoring team in 2011 (35.0 points per game), and the 49ers had the No. 2 scoring defense (14.3). The potent Packers, led by QB Aaron Rodgers and arguably the league’s best wide receivers, torched opponents through the air all season. Not once in their march to 15-1 did they face a team that finished in the top 11 in scoring defense -- the Chiefs, the only team to beat the Packers, were 12th. This will be a huge test to see what the vaunted offense can do against a top defensive unit.

Who matters: WR Greg Jennings and TE Jermichael Finley. The talented pass-catchers are two of Rodgers’ favorite targets, with Jennings the most reliable and Finley the most dynamic. But thanks to injuries and personal issues, the two played sparingly in the preseason. Jennings missed the first two games, then departed early with the starters in the finale. Finley didn’t play a snap until the final game and got virtually no work with the starters. The offense looked out of sync. Rodgers needs to be in a groove with his receivers, especially Jennings and Finley, for the Packers’ no-huddle offense to be successful.

Key matchups: 49ers TE Vernon Davis can be a devastating offensive force. He’s similar to Finley. Both are big (6-foot-3, 250 pounds), athletic matchup nightmares. Davis caught 67 passes for 792 yards and six TDs in 2011. The Packers struggled against elite tight ends last season because their inside linebackers weren't good in coverage. A.J. Hawk is a below-average pass defender and D.J. Smith -- who replaced injured Desmond Bishop -- is small (5-11, 239). Both could get lit up by Davis if the Packers don’t give them help.

Injuries of note: RB James Starks is out with turf toe. Starks hasn’t played or practiced since the preseason opener. The Packers will miss the running ability of their leading rusher from 2011 (578 yards). He’ll be replaced by veteran Cedric Benson, who was signed midway through training camp. Though it hasn’t been made official, CB Davon House is also likely going to miss Sunday’s game. He dislocated his shoulder a month ago, only returned to practice this week and is wearing a restrictive harness that has hampered his play. There’s been no announcement on who will be the right cornerback, the position House figured to start at before the injury. It will be either physical veteran Jarrett Bush or speedy incumbent Sam Shields.

Inside stuff: The Packers spent their first six draft picks in April on defensive players, and the first three -- OLB Nick Perry, DE Jerel Worthy and CB Casey Hayward -- have gotten the most attention. But fourth-round S Jerron McMillian had a solid training camp and lived up to his hard-hitting reputation in preseason games. Though it’s still unknown who will be listed as the starting strong safety in the base defense -- the Packers play so much nickel that it’s mostly a nominal title -- but against Frank Gore and the rush-heavy 49ers, McMillian could be the better choice over M.D. Jennings. McMillian plays the run far better and brings a needed physical presence to Green Bay’s secondary.

Connections: The connection that always comes up when these teams play is at quarterback. In 2005, the 49ers chose Alex Smith first, and Aaron Rodgers fell to the Packers at No. 24. We all know how those selections turned out. Making it all the more interesting is that Green Bay coach Mike McCarthy was San Francisco’s offensive coordinator at the time. The questions come up time and again, but when Rodgers was asked about the connection this week he was diplomatic and complimentary. “We both dealt with some adversity,” Rodgers said. “I don't think [Smith] is a game manager. I think he's a guy who takes care of the football and makes a lot of plays.”

Stat you should know: Turnovers. Both teams finished with an NFL-high 38 takeaways on defense last year. The Packers led the league in interceptions (31), while the 49ers led the league in fumbles recovered (15). San Francisco’s plus-28 turnover differential in 2011 was the highest in the league; Green Bay’s plus-24 differential was second. According to the Elias Sports Bureau, it was the first time since the 1970 AFL-NFL merger that two teams each posted turnover differentials of plus-24 or better in the same season.

Record watch: The Packers have won five straight season openers (2007-2011), which matches the franchise record from 1980-1984. They are also one of only two teams (Patriots) in the league to win their last five season openers.

Bulletin board quote: 49ers WR Randy Moss, who while a member of the Vikings infamously celebrated a touchdown against the Packers by pantomiming mooning the Green Bay crowd, on returning to Lambeau Field: "I try to have fun with the fans, try to have fun. But at the same time, I want to go out and compete. So I think it's a good thing that my comeback -- or whatever you want to consider it -- Lambeau's a nice place to start it.”

Looking ahead: The Packers have a vicious schedule the first month of the season. Even if they survive the 49ers, who went to the NFC Championship Game last year, they have to play the rival Chicago Bears four days later on Thursday. Then they travel out to Seattle to play the Seahawks on Monday night in Week 3 before returning home to face the dangerous New Orleans Saints.

Prediction: Packers 23, 49ers 17

Follow Packers reporter James Carlton on Twitter: @CBSSportsNFLGB and @jimmycarlton88.