Despite an impressive showing by QB Alex Smith against the Cardinals last Monday, the Cards' defense has been their strength this season. Even after Smith's great game, their defense is still ranked No. 6 (two spots ahead of the Packers) by Football Outsiders. Which means the Packers' offense is going to need to play better than it did last week against the Jaguars, and injuries might hold them back.
Mike McCarthy is still thinking happy thoughts about WR Jordy Nelson and said he's a game time decision, but he didn't practice at all this week. It's hard to learn the game plan if you can't practice, and I can't think of another player in recent years who's missed an entire week of practice but still played in that week's game.
Against the Jaguars, the absence of Nelson, in addition to WR Greg Jennings's continued absence, showed how ineffective the offense can be when QB Aaron Rodgers lacks good receivers. WR James Jones and WR Randall Cobb are an effective one-two punch, but he really needs a third option. Which is probably why Mike McCarthy had a one-on-one meeting with TE Jermichael Finley to help re-discover "Finley...The Beast."
On the other hand, all the Packers need is three scoring drives for the win. The Cardinals offense appears to be broken and they haven't scored more than 16 points in any of their previous four games (all losses). Having the 49ers hold you to 3 points is one thing, but they've also been stopped or shut down by three other teams who aren't known for their defense (Rams, Bills, and Vikings).
However, the Cardinals offense (ranked No. 30 by Football Outsiders) is actually one spot better than the Jaguars, who did manage to score 15 points (and keep it close) last week against the Packers. They have to learn some lessons from last week and play better. One obvious spot of improvement is at outside linebacker, where the absence of LB Nick Perry has provided more playing time for LB Erik Walden, who did nothing last week against a poor offensive tackle. The Cardinals don't have quality offensive tackles either, and if Walden turns one of them into a competent player, it could provide the Cards with a much needed boost. At the very least, giving LB Dezman Moses more snaps couldn't hurt.
Still, the Packers haven't been held under 22 points at home this season, and the Cardinals haven't scored more than 20 points on the road. This game is going to be closer than it would have been if Jennings or Nelson was healthy, but there's no reason the Packers can't manage another ugly 24 to 15 type win.