Bears at 49ers -- Week 12
Where: Candlestick Park, San Francisco (grass, outdoors)
When: Monday, 8:30 p.m. ET (ESPN)
Spread: 49ers by 6
Forecast: Partly cloudy, high 50s
Records: Bears (7-2, 1-1 in NFC North); 49ers (6-2-1, 2-0-1 in NFC West)
Past results: Two most recent meetings -- Nov. 12, 2009: 49ers 10, Bears 6; Oct. 29, 2006: Bears 41, 49ers 10. San Franciso has won the last 7 at home against the Bears.  Series Record: 49ers lead 30-27-1.
What matters: The Bears' lead in the NFC North has shrunk to one game over the Green Bay Packers and they play in a place where they haven't won since their Super Bowl-winning season of 1985. They face the league's third-ranked defense with backup QB Jason Campbell starting in place of Jay Cutler, who suffered a concussion last week. The Bears went 1-5 without Cutler last year and acquired Campbell in free agency to prevent something similar. The game could eventually be huge for playoff seeding and a first-round bye, with the Bears currently seeded second and the 49ers third. The Bears' run defense ranks fourth in the league comes up against Frank Gore and a 49ers rushing attack ranked No. 1 in the NFL.
Who matters: Campbell has played in each of the last three Bears' games, including an 11 of 19 second-half effort for 94 yards last week against Houston. But he hasn't started a game since breaking his collarbone against Cleveland on Oct. 16, 2011. Campbell usually opts for the safe route, completing 60 percent or better in seven of the last 10 games that he's thrown a pass, but also averaging less than 6.0 yards per attempt in seven of those 10. ... Bears RB Matt Forte has to be wondering what will drag him down first, a 49ers defense ranked seventh against the run or cobwebs. The Bears have given him the ball more than 16 times in a game only twice this season. With 176 yards receiving, he's on course for the lowest receiving yardage total in his five-year career. ... WR Alshon Jeffery returns from a hand fracture after making 14 catches the first five games, including two TDs. Jeffery gives Campbell a viable downfield threat besides WR Brandon Marshall. ... CB Tim Jennings comes in with an NFL-best eight INTs and leads a secondary that isn't certain whether it will be trying to stop QB Alex Smith, who had a concussion, or backup QB Colin Kaepernick. Regardless, Jennings or the other defenders don't figure to get many chances at INTs against San Francisco's ball-control running and passing games.
Key matchups: Bears LT J'Marcus Webb against 49ers LB Aldon Smith, the NFC sacks leader with 9 1/2. Smith doesn't just sack QBs -- he likes to drive right through them with his tackles. Webb has blocked better and  committed fewer penalties this year than at this point last year, but offensive coordinator Mike Tice has provided him with plenty of assistance. It's doubtful they can do this again with other strong pass rushers like Justin Smith in a scheme (3-4) that gives the Bears problems. ... Bears S Major Wright covering 49ers TE Vernon Davis. With Brian Urlacher needed more in the run game, the Bears will more likely have their strong safety in coverage on the 49ers' speedy TE threat who can get downfield like a wide receiver. The Bears won't have the luxury of playing two-deep, cover-2 in this one much due to the threat from Gore, and Davis could get open downfield. ... Bears WR Alshon Jeffery against 49ers CB Carlos Rogers. Jeffery likely will get to run patterns against single coverage as the 49ers cheat their coverage in any one of several variations to Brandon Marshall's side of the field. Jeffery won't be going against a raw rookie as Rogers is an eight-year veteran coming off his best season ever in terms of interceptions (6). The big height edge won't be on Jeffery's side this game. At 6-3, he has just three inches on Rogers.
Injuries of note: Besides Cutler's concussion, DE Shea McClellin is suffering from a concussion and it reduces the defensive line depth. The Bears will also be without NT Matt Toeaina (calf), so it may mean DE Cheta Ozougwu is active for the second time.
Inside stuff: The Bears could turn to rookie TE Evan Rodriguez in the passing game for the first time. He's been at fullback all year, but TE Kellen Davis is coming off a poor effort and offensive coordinator Mike Tice has hinted they need to find another threat to take advantage of coverage devoted to Brandon Marshall.
Connections: Bears starting LG Chilo Rachal was a second-round 49ers draft pick in 2008 who started 38 games over four seasons in San Francisco before  being signed in free agency by the Bears.  ... Bears LB Blake Costanzo was a key special teams player for the 49ers last year in their run to the NFC title game. ... 49ers coach Jim Harbaugh was a 1987 Bears first-round draft pick who played seven seasons in Chicago.
Stat you should know: The Bears are 9-2 on Monday Night Football under coach Lovie Smith.
Record watch: Jennings is only two INTs short of the Bears team record set in 1990 by S Mark Carrier (10).  ... Devin Hester remains one behind Deion Sanders for the most combined TD returns (INT-fumble-kick-punt) in NFL history.
Bulletin board quote: "He's just kind of there to just not … don't mess up the game." -Bears DT Henry Melton on 49ers QB Alex Smith

Looking ahead: The Bears return home for a Nov. 25 game against the Minnesota Vikings, just their third divisonal contest.
Prediction: 49ers 20, Bears 9

Follow Bears reporter Gene Chamberlain on Twitter @CBSBears.