After the Broncos' Nov. 24 loss at New England, C.J. Anderson called that night the coldest he'd ever been.

After their Dec. 8 victory over Tennessee in Denver, Montee Ball said the football felt like a block of ice.

Don't let this week's balmy temperatures fool you: January is beckoning. January, cold-weather football and the concerns it brings.

The concern now is Denver's running game. It's Anderson and Ball, Ronnie Hillman and Knowshon Moreno. The concern is that with every subtle slide of the mercury, the Broncos' four running backs get ever more important, and yet the passing game all season has proven more trustworthy.

The question is how reliable the running game has been, and how reliable it will be, and how foreboding those 18 yards rushing last week against San Diego are.

Once the regular-season wraps in barely more than a week, every remaining game will be a threat for snow, ice, wind and cold, cold, cold. What that means, of course, is that the Broncos need to run, run, run — not all the time, and not even for the bulk of their yardage, but at least enough to pose a significant threat.

"You see teams that make it to the championship, (and) they're running the football," said Broncos wide receiver Eric Decker. "That is something that, we've got some good backs, we've got a good offensive line and we've been making strides every week. So that's a focus of ours."

And, no, those 18 yards don't spell doom, not after the strides the young running backs, especially Ball, have made. Instead, they're a wake-up call: Do better, and do better soon.

"It gives you something to improve on throughout the week so you don't get complacent," Ball said. "Have your little to-do list of what you need to correct and move on from there."

At face value, there's been no correlation between rushing more or less and winning for the Broncos this season. The night when the running backs had their fewest yards — last Thursday's 18 — yielded a loss, as did the night when they posted a whopping season high of 280 at New England. The other Denver loss: When they put up their second- fewest yards rushing of the season, with 64 at Indianapolis on Oct. 20.