49ers at Saints -- Week 12

Where: Mercedes-Benz Superdome, New Orleans, La. (indoors, artificial turf)

When: Sunday, 4:25 p.m ET (Fox)

Spread: 49ers by 1

Records: Saints (5-5, 1-2 NFC South); 49ers (7-2-1, 2-0-1 NFC West)

Past results: Two most recent meetings -- Jan. 14, 2012: 49ers 36, Saints 32 at Candlestick Park in the divisional round of the NFC playoffs; Sept. 20, 2010 -- Saints 25, 49ers 22 at Candlestick Park. Series record: 49ers lead 46-24-2, including their win last year in the playoffs. San Francisco has a 19-11 advantage at the Superdome but has lost four straight there dating back to 2002.

What matters: San Francisco holds a 1.5 game lead in the NFC West ahead of Seattle and is currently slated to be the No. 2 seed in the NFC playoffs. New Orleans, which started the season 0-4, has won five of the last six and is back in the playoff picture. Based on a developing pattern, the 49ers are in line to play well Sunday. They started the season with two good showings, then took a step back. The same thing happened over the next three games, then again in the three after that. If the pattern holds true, the 49ers should be dialed in for the Saints, who they knocked out of the playoffs last season.

Who matters: Colin Kaepernick. All signs point to Kaepernick being the starting QB on Sunday, but there has been no official word from Harbaugh or the coaching staff. He was brilliant in his first career start Monday when he led the 49ers to a 32-7 win against Chicago and its highly-ranked defense. He was on point with his downfield throws -- so much that TE Vernon Davis likened one throw to one that might have been thrown by Patriots QB Tom Brady. Kaepernick’s performance drew strong reviews from guys like Davis, WR Michael Crabtree, Harbaugh and offensive coordinator Greg Roman. Unlike Smith, Kaepernick was willing to take chances downfield, and in his only appearance he didn’t turn the ball over. All things considered, Kaepernick appears to provide more of a deep dynamic than Smith, who was playing at a high level.

Key matchup: LB Aldon Smith vs. Saints OL. Smith will line up mostly on the right side but also will rush from the left on some plays -- about five to 10 times a game. He came 1.5 sacks shy of the NFL single-game sack record against the Bears when he got to Jason Campbell 5.5 times and is on pace to record more sacks in his first two years than anyone in NFL history. He’ll have his work cut out for him this week as Saints QB Drew Brees has only been sacked 16 times despite having thrown the ball 401 times through 10 games.

Injuries of note: Alex Smith was officially listed as questionable due to the concussion he suffered against the Rams on Nov. 11. He passed his final concussion test Friday and would be cleared to play pending any recurrences of concussion symptoms. Harbaugh said there have been no concussion symptoms since Tuesday. CB Tarell Brown (knee), CB Chris Culliver (shoulder), S Dashon Goldson (ribs, calf), LB Tavares Gooden (shin), RB Frank Gore (wrist, ribs), WR Randy Moss (finger), LB Aldon Smith (shoulder), S C.J. Spillman (finger), DT Will Tukuafu (wrist, wrist) and LB Patrick Willis (shoulder) are all listed as probable.

Inside stuff: San Francisco is familiar playing against Saints defensive coordinator Steve Spagnuolo's scheme; he previously served as the coach of St. Louis in the NFC West. “You can see some of the fronts and defenses that they use -- [he has] incorporated some of (former Saints DC) Greg Williams’ style of defense. But this is much like the St. Louis defense that we saw twice last year, Spagnuolo’s defense,” Harbaugh said.

Connections: 49ers RB Frank Gore and Saints LB Jonathan Vilma were high school and college (Miami) teammates. … 49ers DC Vic Fangio was the Saints DC from 1986-94.

Stats you should know: 49ers WR Michael Crabtree ranks tied for first in the NFL with 22 receptions on third down.  … The 49ers have held their opposition to a TD or less in five of the last seven games, while Brees has thrown for a TD in an NFL-record 53 straight games. … The 49ers ranks No. 1 in the NFL, averaging 165.5 rushing yards per game and their defense ranks No. 1 in the NFL in scoring (13.4 ppg).

Record watch: LB Aldon Smith needs 2.5 sacks in the final six games to set the new NFL record for sacks in a player’s first two years. Reggie White holds the record (31).

Looking ahead: The 49ers will head back on the road next week for a rematch with St. Louis before returning home to play the Dolphins on Dec. 9. A trip to New England follows before divisional games with Seattle and Arizona close out the regular-season schedule.

Prediction: 49ers 31, Saints 24

Follow 49ers reporter Kyle Bonagura on Twitter @CBS49ers and @KyleBonagura.

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