Here are this week's keys to the game:
Gang up on Gore
Perhaps the best player on the field will be 49ers running back Frank Gore, who ranks third in the league with 1,217 yards rushing.
San Diego's LaDainian Tomlinson is hailed as the league's most explosive runner, but Gore's 5.5 yards per rush is better than Tomlinson's 5.2.
New Orleans provided the blueprint to stop the 5-foot-9, 212-pound dynamo, who slipped to the third round of the 2005 draft because he tore both ACLs while playing collegiately at Miami. The Saints held him to 40 yards on 12 rushes after posting consecutive games of 159 yards against Detroit, 212 against Seattle and 134 against St. Louis.
"He's a downhill runner who runs very hard," Packers linebacker A.J. Hawk said. "He uses his leverage great, and he has speed to run away from everybody. He's definitely one of the best backs."
Put the game in Smith's hands
So what did the Saints do? They put eight men in the box and dared second-year 49ers quarterback Alex Smith to beat them. When Smith couldn't make the Saints pay, the 49ers were held to 10 points in a 24-point loss.
"When people disrespect your passing game or respect your running game, however you want to look at it, you need to make plays in all phases. That's really what it will come down to for us to win the game," 49ers coach Mike Nolan said.
Smith has made giant strides since last season, when he threw one touchdown pass, 11 interceptions and compiled a 40.8 passer rating in nine games after being the No. 1 pick in the draft. This season, he's completed 59.9 percent of his passes with 12 touchdowns, 12 interceptions and a 76.3 rating.
In his last two games, though, he's completing only 51 percent of his passes with two touchdowns and five interceptions.
"As part of everyone's maturity, there are bad days that you hope you can learn from," Nolan said. "Not everybody performs at their highest level in their second year as a quarterback in the NFL. Week in and week out, there is a growth and a maturity that goes with it."
Packers pass defense
Smith might be struggling, but Green Bay's pass defense has been a season-long problem.
Battle is a possession-type receiver, and he's got to be licking his chops after watching the Jets' Jerricho Cotchery get open repeatedly with intermediate routes last week.
Eric Johnson, one of the NFC's top pass-catching tight ends, is out with a knee injury sustained in practice, so Davis, who missed six games with a broken right leg, will start. Davis — who was the sixth overall selection, one pick behind Hawk — has only seven catches all season. With his speed and the problems the Packers have had defending tight ends — they couldn't handle the Jets' Chris Baker — this could be a breakout game for the uncommonly fast Davis.
Meantime, pressuring the young Smith would be a big help. To that end, starting defensive end Kabeer Gbaja-Biamila will be replaced on some running downs by Corey Williams. The hope is having KGB fresh on passing downs to do what he does best: rush the passer.
"(The coaches) are trying something. It may work, I don't know. You won't know unless you try it," Gbaja-Biamila said.
Brett Favre was having quite the comeback season after a disastrous 2005 campaign, but his last three games are bringing into question his ability to lead the offense at 37 years old.
In losses to New England, Seattle and the New York Jets, he's completed 51 of 98 passes, with two touchdowns, five interceptions and a passer rating of about 54.
"I really thought I could be a difference maker," Favre said after last week's debacle against the Jets. "I've always felt that was, and I still believe that. But there are games like this and halves like we had in the first half where you go, ‘Huh, what a difference-maker you were. Did you make the right decision is coming back?'"
Facing a suspect 49ers secondary that might be without its top cover man, Shawntae Spencer, for a third straight game, Favre has to be a difference maker if the Packers are going to break out of their funk. He also must avoid mistakes; Walt Harris has six interceptions, is the reigning NFC defensive player of the month and most likely will try to blanket Green Bay's only legit target: Donald Driver.
It's been a weekly question: What happened to the Packers' running game? Through ineffectiveness or lack of opportunities, Green Bay's rushing attack has been missing in action for the last month.
Ahman Green managed 102 yards on 14 attempts against the Jets, but a lot of that damage came after the game was well in hand.
Still, Green needs only to average 53 yards per game to top 1,000 yards for the season, a testament to his arduous offseason after suffering a season-ending thigh injury last year.
Expect the Packers to give the ball to Green frequently, for a change, since veteran 49ers middle linebacker Derek Smith, the team's leading tackler the past six seasons, is out with an injured hamstring. The 49ers have allowed 330 rushing yards the last two weeks, including a season-high 190 last week at New Orleans.
"We've got to get back to that formula that has been successful for us, which was obviously stopping the run on defense," said Jeff Ulbrich, who will replace Smith in the middle. "The past two weeks, we haven't done as well, and we just have to re-emphasize that."
Steve Lawrence is a regular contributor to PackerReport.com. Send comments to email@example.com.