Season of change: These are not your 2011 49ers. The three players most instrumental in San Francisco's divisional victory over New Orleans last season -- Justin Smith, Alex Smith and Vernon Davis -- enter this game on different terms. Justin Smith will try to play through a triceps injury that has sidelined him for three weeks and will require surgery in the offseason. Alex Smith gave way to Colin Kaepernick as the starting quarterback in Week 11. Davis, who caught 10 passes for 292 yards and four scores in the playoffs one year ago, has six catches in his last six games. Kicker David Akers, who set an NFL record for field goals last season, struggled enough recently for the team to sign Billy Cundiff. Who are these 49ers, anyway? Tune in Saturday to find out.
Just in time: Justin Smith appears to be critical to the 49ers' defense. The team allowed 4.5 yards per play with him on the field and 5.1 per play without him this season. Opponents took a sack once in every 14.8 drop-backs with Smith on the field compared with once every 26.8 drop-backs without him. The 49ers forced a turnover every 41.2 plays with Smith and every 57 plays without him. Without Smith contributing at a high level, the 49ers will have a tougher time pressuring QB Aaron Rodgers with four-man rushes.
Something has to give: Rodgers had 22 touchdown passes and only three interceptions on the road this season. The 49ers' defense has allowed seven touchdown passes while picking off six passes at home. San Francisco held Rodgers, Tom Brady and Drew Brees far below their usual Total QBR scores this season. In the divisional round last season, New Orleans' Brees completed 40 of 63 passes (63.5 percent) for 462 yards and four touchdowns, with two picks and three sacks against San Francisco. His NFL passer rating (93.5) and Total QBR score (63.1) were good, but the Saints still lost.
Not much of a rush: The 49ers are facing a Packers team that went all season without producing an individual 100-yard rusher. The 1981 49ers were the last team to win a Super Bowl without having a 100-yard rusher during the regular season. The 1970 Baltimore Colts and 1966 Packers also won Super Bowls without one. 49ers RB Frank Gore hasn't hit 100 yards rushing in a game since doing so against Seattle in Week 7. He has eight 100-yard games over the past two seasons, but none after Week 8. Gore averaged 5.6 yards per rush in the playoffs last season, but he got only 29 carries in two games.
Watching for Woodson: The 49ers must watch for Packers safety Charles Woodson, who is returning from a broken collarbone. Green Bay has been about 50 percent more likely to blitz with a defensive back when Woodson is on the field. Kaepernick has completed 13 of 20 passes for 158 yards (7.9 per attempt) with no touchdowns or picks when opponents rush at least one defensive back. Former starter Alex Smith had a higher NFL passer rating (116.0 to 89.2) and QBR score (82.0 to 65.3) against DB pressure during the regular season. Smith led the NFL in completion percentage (73.0) against all forms of added pressure, completing 11 of 12 such attempts against Green Bay in Week 1. Kaepernick is at 57 percent completions against five or more pass-rushers.
ESPN Stats & Information contributed to this item.