Playoff spots can't be won in October, but they sure can be lost...usually.

The division races are taking shape, and by the end of the month at least a few playoff spots should be somewhat decided. There are plenty of teams at the top, and two or three of them will use the next four weeks to separate themselves from the pack.

The question, then, is which ones? There are five teams left who haven't lost, but only one game features two of them against one another. There are four divisions with at least two teams tied at the top, but none of those ties will be played out on the field in October (including the three teams atop the AFC North).

Oh, and Peyton Manning playis his first game in Indianapolis as a Bronco, in a game that should have playoff implications. So there's that, too.

That makes this an intriguing month coming up. There could be anarchy in the standings, or we could be very close to where we are now heading into a November free-for-all. With that in mind, here are ten games (in chronological order) that could define the season, one way or another.