Only half the teams that participated in the postseason last year earned a playoff date this season. Four of them are in action today including the two teams that met in last year’s Super Bowl, the Tampa Bay Buccaneers and Kansas City Chiefs.

The Buccaneers and Chiefs are hosting their Divisional Playoff games today and both are favored to advance. Tampa Bay over the Los Angeles Rams and Kansas City over the Buffalo Bills.

Last night, while I was doing my calls to the casinos to get wager patterns on these games, one of my favorite people in the business who manages one of the sports books said to me,”You know four underdogs have never won in this round of the playoffs.”

Whenever I hear a stat like that, I go to my library and research for confirmation. He told me about no Divisional Playoff weekend with all four underdogs winning in the wake of both underdogs gaining outright victories yesterday, with the Cincinnati Bengals and San Francisco 49ers ousting the two number one seeds in the American and National football conferences respectively.

I responded to his assertion that we have never had four underdogs win in the same year in the Divisional round with the question of when was the last time both number one seeds were beaten in their first postseason game?

Here are facts.

While it is true that four underdogs in this round of the NFL playoffs have not all won straight-up in the same weekend since the National Football League adopted the seeding rules for home field advantage in the playoffs in 1975, twice the underdogs have swept the point spread decisions. That would be in 2003 and 2006.

As for my query on whether both top seeds had ever been eliminated in their opening game, the answer is they have. Most recently in 2010, when the New York Jets upset the top seed New England Patriots and the Green Bay Packers began their journey to Aaron Rodgers’ only Super Bowl win with the Green Bay Packers when they upset the top seed Atlanta Falcons.

In all, in the Divisional round of the playoffs since 1975, favorites have won 128 of 186 games with a point spread record, including yesterday’s two losses, of 91-90-5. That means 19% of straight-up winners in Divisional games have their triumph reversed by the point spread, which is 3% higher than the percentage of games underdogs win against the spread while losing the games straight-up in the regular season.

It is a slight edge, but it does mean that points on the spread are more valuable in the Divisional Playoff Round than in the regular season.

Is that enough of a reason to justify two more underdogs winning today?

No.

But for those that want to discard the possibility of all underdogs winning straight-up or at least against the point spread, I throw this caution to that thinking. Statistics and trends are subservient to the unique factors that dictate results in every game. While some deciding factors are only illuminated after the games are played with the benefit of the actual results, the criteria in Tampa and Kansas City today are not affected by what happened yesterday in Tennessee or Green Bay.

The only absolute requirement for a second week of the playoffs sweep by the underdogs is wins yesterday by the Bengals and 49ers. Whether the Rams and Bills are able to complete the first ever underdog four game winning streak in the Divisional Round will not be decided by any results before or after their games, only what factors will dictate the final scores in these two contests.

I have indicators that show both defending conference champions are going to lose today, with Los Angeles beating the Buccaneers and Buffalo downing the Chiefs. On their own, the edges are clear, while when grouped with yesterday’s results, they look singularly unexpected.