Rule of 72: Three drivers out

Editor's note: An explanation of Ricky's "Rule of 72" can be found here.

The Chase for the Sprint Cup heads into a critical week in Martinsville with three more drivers eliminated from contention under the Rule of 72. With four races to go, I maintain that this is still a three-horse race between Brad Keselowski, Jimmie Johnson and Denny Hamlin.

Jeff Gordon, Kevin Harvick and Greg Biffle are the drivers eliminated this week as a result of their finishes at Kansas. Harvick and Biffle have exceeded 72 points under the Rule of 72. While Gordon has 70 points, with four races left, there's no way he can stay under 72 points entering the last race of the season. So we say goodbye to those three drivers, who join Matt Kenseth and Dale Earnhardt Jr. among those eliminated. That leaves seven drivers in the Chase under the Rule of 72.

Among those seven, Tony Stewart is the closest to the bubble under the Rule of 72. He's at 64 points and needs a minimum fifth-place finish at Martinsville to stay in contention. Martin Truex Jr. has a little more room for error at 57 points, while Kasey Kahne and Clint Bowyer are each at 47 points.

But the one to watch this week is Denny Hamlin, who sits in third in the Rule of 72 standings at 42 points. This time of year is about overachieving, and thus far, Hamlin's No. 11 team has not overachieved. This weekend needs to serve as the turning point for Hamlin's championship quest.

With four races to go, time is running out. But the good news is Hamlin couldn't have chosen a better track to be at this week, as he's won three of the past six Martinsville races. The half-mile track in Hamlin's home state of Virginia could certainly serve as a catalyst for change.

It was clear to me that Hamlin was frustrated after his 13th-place finish last week at Kansas. It likely added to his frustration that the No. 48 car of Johnson wrecked and still finished ahead of Hamlin, which was an amazing accomplishment.

Johnson's recovery last week was one for the ages. At least a dozen things needed to happen or fall into place for Johnson to overcome his wreck midway through the Kansas race. Among those factors: timely caution flags; a well-prepared crew; a synchronized effort by the car chief, crew chief and all crew members to repair the damage.

In the end, Johnson turned what appeared to be a 25th-place finish into a ninth-place finish. Thanks to his efforts and those of his team, Johnson lost no ground to Chase leader Keselowski.

Meanwhile, Keselowski continues to do everything right. He and crew chief Paul Wolfe are now six races into the Chase, and through those races they are averaging a little under a sixth-place finish. That performance is worthy of a championship.

In the history of the Chase, every driver who has won the championship has finished in the top five at Martinsville. So if you believe in history, finishing fifth or better this week is essential to your championship chances.