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Pittsburgh safety Troy Polamalu (43) breaks up a play against San Diego on the final play of the Nov. 16 game in Pittsburgh. The Steelers won, 11-10, and play host to the Chargers again this weekend in the divisional round of the NFL playoffs.

By Jeff Haney (contact)

Thu, Jan 8, 2009 (2 a.m.)

All four games in the divisional round of the NFL playoffs this weekend are rematches not only of regular-season games, but of close regular-season games.

The five games — including two meetings between the Eagles and Giants — were each decided by six points or fewer.

In the Titans’ 13-10 victory against the Ravens, Tennessee quarterback Kerry Collins needed a fourth-quarter, 11-play, 80-yard drive along with a disputed personal-foul call against Baltimore to secure the game and stay unbeaten for the time being.

The Steelers squeezed past the Chargers, 11-10. The Cardinals, who were blown out several times on the road, kept it close at Carolina before losing 27-23 — but covering a 5-point spread.

The Eagles lost at home, 36-31, but won 20-14 at Giants Stadium in the latest two skirmishes in a rivalry marked by wild and unpredictable finishes for the past two decades. (Paging Herman Edwards and Joe Pisarcik.)

All of which makes it quite tempting, at least at first glance, to back the underdog at the betting windows this weekend.

The Cardinals are getting 10 points in Las Vegas against the Panthers, and the Ravens are a 3-point underdog against the Titans in Saturday’s games. On Sunday the Eagles are getting either 4 or 4 1/2 points, depending on where you shop, and the Chargers are an underdog of 6 to 6 1/2 points against the Steelers.

But that temptation might end up being one of those near occasions of sin you’re supposed to avoid.

Games in the divisional round historically have had the widest margins of victory in the NFL playoffs, as Las Vegas author and handicapper Andy Iskoe pointed out in his “Logical Approach” newsletter.

In the 198 games since the NFL adopted its current 12-team playoff format in 1990, the average margin of victory in those games was 13.3 points, according to Iskoe’s research — a fairly wide margin in itself.

Yet the margin in the divisional round of playoff games has been the highest at 14.1 points, according to Iskoe (online at thelogicalapproach.com), well ahead of the average of 12.5 points in the wild-card round.

The reasoning behind the results appears sound: Divisional playoff games tend to feature rested home teams that have established themselves among the league’s elite over the course of a season, off a bye week to prepare for lesser teams that might have barely qualified for the playoffs and just played an elimination game the previous week.

Home teams and betting favorites have been particularly effective in the NFL divisional playoffs, Iskoe pointed out, with home teams 55-17 straight-up and favorites 52-19 straight-up since 1990.

Still, as so often happens in sports betting, there’s a valid opposing view as well. Results vis-a-vis the point spread have been mixed, with favorites of a touchdown or more going 25-15-1 against the spread but favorites of 3 1/2 to 6 1/2 points just 7-11 against the number.

And in recent years, betting on road underdogs has been a winning proposition in the divisional round of the playoffs. Last year three of the four road underdogs covered the spread, according to Iskoe, and the previous year all four road ’dogs covered the spread for the second time in four seasons.

Of the four longest shots to win the Super Bowl, according to odds posted at the Las Vegas Hilton sports book at the start of the playoffs, only the Cardinals survived the opening round.

Arizona was installed as a 50-1 shot at the Hilton after the conclusion of the regular season, and is still about 30-1 to win the Super Bowl, the highest odds by far of the remaining teams.

Odds on the other teams to win the Super Bowl range from 3-1 on the Giants to 10-1 on the Chargers.