Editor's note: For an explanation of the Rule of 72, click here.
The list of Chase for the Sprint Cup drivers eliminated by the Rule of 72 is longer now after last week's race at Talladega.
Kurt Busch joined the list of drivers eliminated from contention with his 18th-place finish, which gave him exactly 72 points under the Rule of 72. Clint Bowyer finished 10th, but at 71 points, he's all but technically eliminated. Busch and Bowyer join Kasey Kahne, Joey Logano, Ryan Newman and Carl Edwards among drivers who have been eliminated from contention.
Barely hanging on is Dale Earnhardt Jr. with 68 points. He would need to win the next three races to go into Homestead with a chance to take the Sprint Cup title. Faring only slightly better is Greg Biffle, who has 65 points and only one top-five finish in the Chase. Unless these two drivers have outstanding finishes at Martinsville, they will soon join their fellow competitors on the list of eliminated drivers.
So who still has a realistic shot at the 2013 title?
Jeff Gordon has had a very consistent Chase so far, but his 14th-place finish at Talladega has left him in a compromised position with four races remaining.
My pick to win at Talladega was Kevin Harvick, but he fell short of that prediction with a 12th-place finish. While Harvick gained ground on Matt Kenseth, he actually lost a point to new points leader Jimmie Johnson.
Kyle Busch was the driver who helped himself the most on Sunday in the Chase standings. His fifth-place finish at Talladega gives him five top-five finishes in six events. The only blemish on his record is his 34th-place showing at Kansas, but that finish is the biggest reason he's 22 points behind Kenseth and 26 behind Johnson in the points standings.
Among those still in contention to win the championship, Kenseth had the most disappointing day at Talladega, He spent much of the day leading the race, but ended it with a 20th-place finish -- his lowest during the Chase -- and the loss of the points lead he had since the Chase began. Johnson finished 13th and didn't really take the points lead away as much as Kenseth surrendered it to him.
To make matters worse for Kenseth and Kyle Busch, the tour's next stop is Martinsville, a track where neither driver has ever won a Sprint Cup race. And oh, by the way: Johnson has dominated at the paper-clip-shaped track, winning there eight times.
What's required to win at Martinsville, the smallest track on the Sprint Cup Series, is a completely different approach and different attitude than what drivers displayed last week at Talladega, the series' biggest track. At Talladega, it's about drafting and avoiding the multicar wreck. At Martinsville, it's about driving as hard as you can, while preserving your tires and brakes for a run to the checkered flag in the last 100 laps.
Every track requires something different -- a different discipline, a different technique, perhaps even a different frame of mind. Martinsville is about being aggressive on new tires, but it's also about knowing how to recognize the threshold where the tires begin to give up and the brakes begin to fade. A driver must be able to recognize that threshold and shift mindsets from being aggressive to preserving the car until the next pit stop.
That's the balance the drivers in contention must maintain if they want to close the gap between Johnson and Kenseth and themselves.