The San Francisco 49ers emerged from Week 17 with a 13-3 record and first-round playoff bye as the NFC's second seed.

They also barely held on to beat the previously 2-13 St. Louis Rams, allowing as many points (27) as they had allowed in a game all season -- despite the Rams' status as the NFL's lowest-scoring team. They have injuries at wide receiver and tight end. Even ironman defensive lineman Justin Smith has been hurting recently.

The question I posed Sunday -- how much should the 49ers be concerned? -- had invited about 350 responses by Monday morning. Let's run through a few of them, with my thoughts interspersed. The 49ers fans I've encountered aren't hurting for confidence.

"Saints and Packers should be concerned," u cant hand1e the truth replied.

Now that's the spirit. And as the unfortunately named @_nutjob_ pointed out via Twitter, the 49ers went 4-1 during the regular season against the current playoff field.

San Francisco won at Detroit when the Lions were 5-0. The 49ers beat a previously 6-2 New York Giants team at Candlestick Park. They won at Cincinnati and dominated Pittsburgh at home. Their only defeat to a current playoff team came at Baltimore on a short week.

"The Packers haven't faced a top 10 defense all year!" larkC23 wrote.

Sure enough, none of the teams Green Bay faced this season finished among the 10 best in fewest yards allowed. Of course, the Packers' offense had something to say about where those teams ranked. Kansas City was the Green Bay opponent with the highest end-of-season ranking for yards allowed. The Chiefs were also the only team to beat the Packers.

Atlanta, which finished 12th in yards allowed, held the Packers to 25 points, their second-lowest total in a victory all season (the St. Louis Rams allowed 24).

Yardage can be an imprecise indicator for a team's strength. Most would agree, however, that the top four teams in yards allowed -- Pittsburgh, Houston, Baltimore and San Francisco -- have good defenses.

Green Bay finished the season ranked 32nd in yards allowed, but first in interception rate and 19th in points allowed. The Packers built big leads, diminishing the value of some yardage gained against them (while also affecting how many interceptions opponents threw while taking chances).

These 49ers were hardly a machine on offense, but they scored touchdowns six times in nine red zone possessions over their final three games, a huge improvement from earlier form. They committed no turnovers over their final five games and had only 10 all season.

Statistical sacrilege

One 49ers fan, Heisenberg, noted that 49ers quarterback Alex Smith produced numbers better than the ones Joe Montana put up while leading the 1981 team to a 13-3 record. This was a subject we discussed in our NFC West Final Word item Friday.

Smith completed 61.4 percent of his passes for 3,150 yards with 17 touchdowns, five interceptions and a 90.7 NFL passer rating this season. Montana passed for 3,565 yards with 19 touchdowns, 12 interceptions and an 88.4 rating. Smith and Montana played in different eras with different supporting casts and different demands placed upon them. Still, the 49ers presumably would have taken Montana's 1981 stat line had it been offered to them before the season.

Smith finished this season with three consecutive strong showings in Total QBR, posting scores in the 70s (out of 100) every time. Avoiding turnovers, limiting sacks, completing long passes in the clutch and scrambling for key gains increasingly made the difference for a team that has often won with defense and special teams. Not that Smith will be mistaken for Aaron Rodgers or Drew Brees.

"This team, as is, is the Super Bowl fave if Montana is behind center," shootme5150 wrote. "No doubt. No disrespect to Alex."

No one is promoting Smith as an all-time great. It's just that Smith has played well enough for the 49ers to win this season.

"People forget that Montana wasn't in his prime when they won that first Super Bowl, and no one knows what we might see from Smith in years to come if Harbaughs keeps him around," Heisenberg wrote.

Smith has become a bigger part of the team's victories in recent weeks. That will presumably need to continue for the 49ers to win their divisional-round game at home on Jan. 14. They will face New Orleans if the Saints defeat the Lions. If Detroit wins, the 49ers would play the winner between Atlanta and the Giants.

"To beat the Saints, somehow, some way the 49ers are going to have to score!" humbleNhungry9er wrote. "There is no way the 49ers have a chance with the mindset of kicking field goals! The 49ers will have to play great defense and score touchdowns to win this playoff game! I'm hoping and praying Jim pulls some plays out the hat!"

We've used up our allotment of exclamation points. I'll have to punctuate this item with something else.

"The Saints lost to the Rams," Giants49ersSharksWarriors777 wrote. "What room do they have to talk?"

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2011 Defensive Rankings