Saints-49ers: Strength against strength

The New Orleans-San Francisco divisional playoff game Saturday pits strength against strength and weakness against weakness.

I've followed up charts from an earlier item with two showing how each team's offense and defense stacks up against the other in 2011 NFL rankings.

The biggest ranking disparities between the Saints' offense and 49ers' defense favor the New Orleans passing game (setting aside fourth-down conversion rate, which suffers from small sample size).

The Saints rank first in third-down conversion rate, sacks allowed per pass attempt and passing yards per game. The 49ers' defense ranks outside the top 10 in those categories. The rankings are quite similar across most categories, however, and disparities provide only a general picture.

2011 Rankings Differential: Saints Offense vs. 49ers Defense

The second chart shows rankings for the Saints' defense and the 49ers' offense. If these units hold to form, the 49ers' Alex Smith will not suddenly start throwing interceptions. But neither will San Francisco suddenly improve its third-down conversion rate.

The 49ers' red zone offense, though ranked only 30th, scored six touchdowns in nine chances over the 49ers' last three games. The Saints' red zone defense fared well against Atlanta twice and also against Houston, but not against the rest of the league. New Orleans ranks 28th in red zone touchdown defense. The Saints allowed four touchdowns in four red zone possessions against Detroit in the playoffs and still won 45-28.

2011 Rankings Differential: Saints Defense vs. 49ers Offense