Jeff Haney does the math and advises against betting on Chicago to go undefeated

Friday, Oct. 20, 2006 | 8:01 a.m.

The Bears' comeback victory against Arizona on Monday night not only kept Chicago's unbeaten record intact, it also kept an intriguing football betting proposition alive in Las Vegas sports books.

Several books are offering a prop on whether the Bears, who improved to 6-0 by beating the Cardinals, will be the first team to finish the season undefeated since the 1972 Miami Dolphins.

At all Station Casinos properties, the Bears are plus-1100 (win $11 for each $1 risked) to go undefeated, and it's minus-1600 (risk $16 to win $1) they will not. Station oddsmakers opened the prop last week, before the Cardinals game, at minus-2000/plus-1500.

The Palms has the same proposition, also offering plus-1100 that the Bears will go undefeated, but requiring "no" bettors to lay only minus-1300 on the other side.

At the Las Vegas Hilton, it's plus-1150 the Bears will go undefeated and minus-1600 they won't.

Note that at those prices, you should bet the "yes" side of the prop at the Hilton or the "no" side at the Palms for maximum value. (As always, odds can and do change by the minute.)

One way to analyze the proposition entails estimating the Bears' chances to win each of their remaining 10 games, expressing that figure in a percentage, then converting it to a money line. Finally, compare that money line to the one available in the sports books and decide if the prop is worth betting.

Using the latest NFL power ratings issued by the Gold Sheet, following is a rundown of what we can expect from the rest of the Bears' schedule:

Tallying those percentages, we find the Bears have about a 3 1/2 percent chance of going undefeated, or a 96 1/2 percent chance of losing at least one game.

That equates to a no-vig money line of minus-2757, or something like a minus-3200/plus-2200 on the betting board. Because the plus-1100 to plus-1150 in Las Vegas is nowhere near plus-2757, or even plus-2200, it appears the value lies on the "no" side.

Does that mean oddsmakers are way off base on this prop? No, it does not, for a couple of reasons. The most obvious is that gamblers are naturally drawn to the "yes" side of the prop. It's exciting to root for an undefeated season while going for a big score. Conversely, risking a lot to win a little on the "no" side is as much fun as purchasing some General Electric shares so you can collect the company's dividend of a couple of percentage points.

Still, if I bet this prop at all, I'll be a "wrong-way" player. Given the current prices in Las Vegas, put me down for the "no," the Bears will not finish the regular season undefeated.