While in many aspects the game figures to be a snoozer (the folks in Vegas certainly think so, as the Niners are 16.5-point favorites, their highest line since 1998), it will be important for the home team in a few respects.
For starters, the 49ers still have a chance to grab the second seed in the NFC and the first-round bye and guaranteed home-field advantage in the divisional round that comes with it. All they have to do is beat the terrible Cardinals and get some help from the Minnesota Vikings, who host the Green Bay Packers.
A 49ers win and a Packers loss means a week's vacation for everybody, and if any team could use the time to rest and recuperate, it's a banged-up 49ers squad. While hoping for a loss from a red-hot Packers team seems like wishful thinking, at least the game is ultra-important for the Vikings, who need to win to make the playoffs, so there's no doubt they'll be giving their best.
Also, Adrian Peterson is still within range of Eric Dickerson's single-season rushing mark of 2,105 yards, so the Vikings will be primed for that one.
Even ignoring the result of the NFC North clash, the game vs. the Cardinals will be important for the 49ers just to capture the NFC West for a second consecutive year.
If they somehow get shockingly upset by Arizona, a Seattle win at home against the St. Louis Rams will relegate the 49ers to Wild Card status, and they'll be on the road next week, taking on the winner of the Dallas-Washington tilt which will settle the NFC East.
Finally, forgetting all the practical implications, it will be important for the 49ers to get a win just to build some momentum going into the postseason. They got waxed by 29 points (and it wasn't that close) and suffered numerous injuries to key players. It's hard to think of another team going into the playoffs with more ominous, negative energy.
Still, it could be worse. They could be the Cardinals.
Arizona started brightly, winning their first four games including a stunner at New England, but have been miserable ever since starting QB Kevin Kolb got injured, dropping 10 of their last 11 games, including a 24-3 loss at home to the Niners on Oct. 29 on Monday Night Football.
Alex Smith completed 18-of-19 passes for 232 yards and three touchdowns in that game and was named NFC Offensive Player of the Week for his efforts. He suffered a concussion against the Rams the next week and has been benched ever since in favor of Colin Kaepernick, who has been stellar in most of his starts but quite mediocre in games within the division.
Brian Hoyer will be making the first start of his career for Arizona, their fourth different starting quarterback of the season. He'll be looking to break a streak of 12 NFC West visiting quarterbacks who have left Candlestick Park without a win, as the 49ers have gone 11-0-1 in their last dozen home games in the division.
Where's Mario? Where's Vernon? Who the hell is that Celek guy?
It's the best of times, it's the worst of times for Colin Kaepernick.
On one hand, it's apparent that his coach, Jim Harbaugh, has fully committed to him as the team's starting QB come hell or high water, and that feeling has to inspire confidence in a young player.
And Kaepernick has played mostly well in six starts and several other appearances throughout the season, compiling a 95.2 passer rating while completing 63.2 percent of his passes with eight touchdowns and three interceptions.
He's scored five more times on his own, and has scampered for 410 yards on the ground, averaging an impressive 6.8 yards per carry.
On the other hand, Kaepernick has struggled mightily against division opponents, losing at St. Louis and at Seattle, while just mustering a tie against the Rams at home.
He continues to have major difficulties getting the team lined up and snapping the ball in time, and Harbaugh's had to waste a lot of time outs to avoid delay-of-game penalties.
Scoring in the red zone has been an issue as well, as has an increased amount of penalties on the offensive line, who are still adjusting to a quarterback who holds onto the ball so long.
Kaepernick is at his best when he has time in the pocket to look aggressively downfield, and he's got the arm to make any throw, forcing defenses to cover the whole field. He's been hampered when aggressively blitzed, however, and hasn't shown much of an inability to throw to the hot receiver in those situations.
Worse for the young quarterback, he's had to adjust to a revolving door of skill players around him. Kendall Hunter, Kyle Williams and now Mario Manningham have all been lost for the season with injuries, leaving rookies LaMichael James and A.J. Jenkins to take their spots.
Vernon Davis missed most of last week's game with a concussion, which led to a lot of playing time for rookie Garrett Celek at tight end.
Given those circumstances, it's understandable why Kaepernick has looked early and often for Michael Crabtree, who has been the only dependable, consistent target among the receivers all season.
It will be important for Kaepernick to put a good game together so he'll have some confidence going into the postseason and to keep the media at bay regarding Harbaugh's decision to go with him instead of veteran Alex Smith.
Kaepernick didn't help himself much with the press following the loss at Seattle, but all will be forgiven (for a week) with a decisive win against Arizona.
Uh oh. This can't be good.
Frank Gore has enjoyed a terrific season overall and deservedly made another Pro Bowl, the fourth time he's been so honored.
However, his game has waned sharply ever since Kaepernick's taken over at quarterback, totaling just 393 yards on 98 carries (4.0 yards per carry). In the previous nine games when Alex Smith started, Gore had 140 carries for 753 yards, a fantastic 5.4 yards-per-carry average.
The team has used a lot more of the "pistol" formation with Kaepernick, and Gore, who has thrived running out of the I or ace (two tight end) formations for years, is not used to it.
About the only good news from last week's one-sided loss at Seattle was that it got out of hand so quickly that the coaching staff saw fit to give Gore the night off, as he only got six carries in the game.
Given the wear-and-tear of the long season, it would behoove the team to put the Cardinals away early so that Gore can again give way to LaMichael James and Anthony Dixon and rest up a bit for the playoffs.
At this point it seems unlikely that the Niners will have a first-round bye, so Gore will need all the help he can get.
At receiver, the Niners are in a bit of a flux, which is a bad position to be in as the playoffs approach.
Michael Crabtree has been the one consistent, and with 933, yards he's poised to be the team's first 1,000-yard receiver since Terrell Owens in 2003.
Crabtree's numbers don't look like much, he's 10th in the NFC in receptions (77), 13th in yards (933) and tied for 14th in touchdowns (7), but considering that the 49ers throw the ball less than just about any team in the league, he's had a really strong season, all things considered.
Crabtree scored twice in the last meeting against the Cardinals, making Pro Bowler Patrick Peterson look bad in the process.
Besides the former Texas Tech standout, there isn't much to be excited about. Vernon Davis has had a disappointing season and he's coming off a game in which he's had a concussion at Seattle.
Davis hasn't practiced with contact all week and while he's likely to be cleared medically for the Cardinals game, he's totaled five receptions for 56 yards in his past five games.
Davis' backup Delanie Walker has come on a bit of late, but he's had issues catching and securing the ball all season.
Mario Manningham joined Kyle Williams on the injured reserve list this week, meaning that aside from Crabtree and graybeard Randy Moss, the team's only receivers are Ted Ginn, who's caught two passes for one yard all season, and first-round pick A.J. Jenkins, who's been a healthy scratch just about the whole year.
The coaching staff will have no choice but to play Jenkins in spots now, but how effective can he possibly be? Walker was lining up at receiver at Seattle once Manningham left with his knee injury.
The offensive line has been mostly a strength all season long. Left tackle Joe Staley and left guard Mike Iupati both were deservedly named to the Pro Bowl team, while the other three starters were all named as alternates (though the pick of Jonathan Goodwin in that regard seems fairly ludicrous to me).
Against the Cardinals, they'll face a front seven that's better than average, but certainly not dominant. The gigantic Calais Campbell needs more support alongside him on the defensive line, while their best player, linebacker Daryl Washington (123 tackles, nine sacks) was a notable Pro Bowl snub.
I'd have put him in over Patrick Willis, as unpopular as that opinion will be.
While Justin Smith's individual stats might be down this season (he only had three sacks), all it took to demonstrate how valuable and critical he is to the 49ers defense was for him not to play.
He exited midway through the third quarter two weeks ago at New England and the Niners promptly gave up touchdowns on four straight drives to turn a 31-3 rout to a 31-31 nail-biter, in a game they went on to win, barely, 41-34.
The next week, at Seattle, they got thumped 42-13, with the defense giving up five of those six scores and allowing the Seahawks to convert 11-of-13 third downs (and one of San Francisco's two "stops" was a kneel-down on the final play of the game).
Need more proof? The defense gave up a season-high 176 rushing yards in the loss to Seattle and have allowed 4.4 yards per carry without Smith, a figure that would rank 21st in the league. With him they allow 3.6 yards per carry, second-best in the NFL.
Finally, there's this: Aldon Smith, who racked up 19.5 sacks the first 13 games of the season playing alongside his fellow Missouri alum, has been shut out in back-to-back games without Smith tying up blockers for him.
Given all that, maybe Smith was deserving of his fourth consecutive Pro Bowl nod after all, though it's doubtful he'll play in that game since he's got a partially torn triceps.
Smith will most likely miss his second straight game this week with the injury, which typically takes three months to heal, but the team is hoping he'll return for the playoffs.
The defense as a whole needs to recover from their sorry showing at Seattle.
Linebackers Patrick Willis and NaVorro Bowman (both named to the Pro Bowl, the sixth in six years for Willis; the first of many for Bowman) both missed a string of tackles.
Aldon Smith never got to Russell Wilson, and bookend pass-rusher Ahmad Brooks was on skates all game and unable to read Wilson's play-fakes.
The corners, particularly Carlos Rogers, had a miserable time in coverage, and safeties Dashon Goldson and Donte Whitner, who both were named to the Pro Bowl (a joke, in Whitner's case), failed to have their usual hard-hitting impact.
In fact, Seattle's safety duo of Earl Thomas and Cam Chancellor proved themselves in that game to be the superior play-making tandem, and once you factor in corners Richard Sherman and Brandon Browner, there's no doubt that the Seahawks boast the best secondary in the division.
One thing about the defense in the Jim Harbaugh era is that they've always responded fantastically after a loss.
The Cardinals, with their inept quarterback situation (Brian Hoyer will be their fourth starter there of the season) and their swinging-gate offensive line, don't figure to trouble them much.
Larry Fitzgerald has caught only 69 passes out of 148 targets and hasn't even cracked 800 yards on the season. That's how poor his passers have been.
Beanie Wells, meanwhile, said in an interview that he's openly showcasing himself for the other 31 teams, figuring that his days in Arizona are coming to an end.
The other 31 teams will no doubt take notice of Wells' 2.7 yards-per-carry average and say "no thanks."
Andre Roberts has had some nice moments opposite Fitzgerald and rookie Michael Floyd has been so-so, but there might be three, four legitimate NFL players on their entire offensive roster.
Alex Smith will have to think long and hard about what he'd be getting himself into with the Cardinals, should that opportunity arise, as many folks have speculated.
Lee won't be kicking it in Honolulu this year.
It sounds spoiled to say for a team that had a league-high nine players named to the Pro Bowl, but Andy Lee was robbed.
Yes, New Orleans' Thomas Morstead had a slightly better net average than Lee, 44.4 yards to Lee's 43.3, but he punted in a dome eight games this season (seven home games plus at Atlanta) while Lee's punted indoors just twice, at the Saints and at the Vikings.
Furthermore, Lee, who is playing for a contender unlike Morstead, has planted nearly twice as many of his punts (35) inside the 20 than Morstead's 18 and allowed 78 less return yards overall.
How anyone could think Morstead is the superior punter is just a sham.
On the other side of the ledger, no one will complain about David Akers not making the Pro Bowl. The 14-year veteran has converted just 27-of-38 field goals (71.1 percent) and finally broke a season-long slump from 40 yards or longer by drilling a meaningless 54-yarder at Seattle.
As far as the returners go, LaMichael James has provided a real boost on kickoffs since taking over there four games ago and has averaged 29.5 yards per return, coming close to breaking a couple for touchdowns.
Ted Ginn lost the kickoff return job to James and hasn't been of much use in punt returns either, averaging a so-so 9.6 yards on 31 chances. He's been more conservative of late, fair catching more of his of opportunities than he had earlier in the season.
The Cardinals, meanwhile, haven't gotten any production from their returners at all. Neither LaRod Stephens-Howling nor William Powell have opened eyes as kick returners and Patrick Peterson, who electrified with four punt-return scores last season, has crashed back to earth in his sophomore campaign, averaging a meager 8.4 yards per return.
C'mon Pete, let's just wrestle at midfield to decide the game. What's the matter, you chicken?
Jim Harbaugh faces an interesting test of game and personnel management this week against Arizona.
He and his staff have to do everything they can to win the game, for obvious reasons, but have to figure out a way to get a result locked up early enough that he can afford to rest all the key veterans for the fourth quarter, if not the entire second half.
While the Cardinals sure don't look like much on paper (they're 16.5-point underdogs), the 49ers have struggled mightily in their divisional rematches this season.
Considering that Justin Smith will be out, that Vernon Davis will be at less than his best and that the offense will most likely be relying on at least one receiver who hasn't lined up much if at all this season (either Ted Ginn or A.J. Jenkins), the game might be a bit more complicated than it appears on the surface.
Ideally Frank Gore would receive a few early token carries and the coaches could ride LaMichael James and Anthony Dixon to a win, but given Colin Kaepernick's inconsistent play and the defense's slump without Smith wreaking havoc, it's just difficult to see the Niners racing out to a comfortable lead.
Defensive coordinator Vic Fangio isn't normally very aggressive, but this sure looks like an opportune time to blitz early and often.
Not only would sending extra men most likely confound an inexperienced started in Brian Hoyer, but it would overwhelm a poor offensive line and help create pressure for a a defense that hasn't been able to produce much of a rush without Justin Smith.
If the defense can create some early turnovers and give Kaepernick and Co. some short fields to work with, it will ease the offense's burden, and they need all the help they can get these days.
Offensive coordinator Greg Roman had an ambitious, go-for-broke game plan against Seattle last week, and while it failed miserably up there, a similar approach should provide better results this time around against a more pliable Cardinals defense probably already thinking about their offseasons.
With the need to save Gore paramount, it makes sense to utilize Kaepernick's arm and legs as much as possible and to give him as many reps as he can handle.
Also, the focus should be in and getting in and out of the huddle quickly and proving that Kaepernick could get past that mental hurdle. It wouldn't be surprising at all to see the team utilize the no-huddle just for that very purpose.
The Niners have to handle their business quickly in this game. The longer it's competitive, the worse it is for everyone involved, and all the bad omens going into January will just get worse.
On the other sideline, Ken Whisenhunt and his staff might very well be coaching their final games for the Cardinals, with "Black Monday" for coaches across the league looming.
Whisenhunt's biggest failure with the Cardinals, and one that he's surely not solely responsible for, is being unable to find or develop a quarterback since Kurt Warner retired.
It's easy to say that the Cardinals' season took a sharp turn for the worse once Kevin Kolb got hurt but really it's been downhill ever since Peyton Manning turned them down in the offseason, favoring Denver instead.
More damning for Whisenhunt has been the fact their offensive line has been every bit as terrible, if not worse, than their quarterbacks, and their collective wretchedness has made it impossible for any passer to survive, much less thrive.