Racing fortunes can be fickle. They can be cruel. They can change in a split-second of miscommunication in 170-mph traffic.

If Brad Keselowski needed a reminder of how external influences could sabotage his NASCAR Sprint Cup championship quest Sunday, he got one Saturday.

Initially in the Ford EcoBoost 400 to be green-flagged at 3:17 p.m., the 28-year-old driver of the points-pacing No. 2 Miller Lite Dodge will be the primary beneficiary of a lineup-scrambling crash during the first of two practice sessions.

On Friday, Joey Logano put in a 176.056-mph claim to pole position for the 267-lap chase over Homestead-Miami Speedway’s 1.5-mile oval.

But he will have to forfeit the prime spot.

In his final start in the No. 20 Home Depot Toyota, Logano drove into innocent-bystander involvement in a three-car skirmish out of Turn 4. Significant damage forced the Joe Gibbs Racing team to pull a backup car off the hauler.

Logano will pull out of line to go to the back of the 43-car lineup during pace laps for the season finale, and the inside line of cars will advance for the Ford 400 launch.

Keselowski, as third-fastest qualifier, will wind up inside front-row with an immediate chance to lead the first lap for a bonus point that would enhance his title prospects.

With a 20-point advantage over five-time Cup champion Jimmie Johnson, Keselowski will ascend his sport’s throne with a finish of 15th or better.

But add a point for leading a lap and it becomes 16th or better.

“If I can take the lead without wrecking myself, that’s what I’m going to do,” Keselowski said. “I think I have the car to do it.”

Most fans may have been inclined to shrug off the importance of a single point, but that was before Tony Stewart and Carl Edwards dueled to a one-two Ford 400 finish and a flat tie at 2,403 points.

Stewart collected his third championship on a tiebreaker.

Johnson’s familiar No. 48 Lowe’s Chevrolet will line up 10th for the green flag with Johnson well aware that he not only must finish ahead of Keselowski, but also by a long way and plenty of positions. The challenge is formidable. But Johnson knows stranger things have happened.

Of Keselowski’s opportunity to get a leader bonus immediately, Johnson quipped: “I hope he tries really, really, really hard. I know [Marcus] Ambrose next to him is going to try hard, too. That could be good for me.”

Logano trailed Denny Hamlin and Greg Biffle into Turn 4 in the fateful practice.

The cars aligned in such a way that Logano could have advanced on the outside to create a three-wide jam. He had no intention of doing so, but Biffle and Hamlin didn’t know that.

Biffle, a three-time winner in the Homestead finale, had an amicable discussion with Hamlin after the incident as all three drivers tried to piece together what happened.

“My spotter told me to leave the 20 [Logano] room because the 20 had a run,” Biffle said. “I wasn’t going to come up in front of him.”

Logano’s view: “It just seemed like Denny was coming up like we were two-wide, and the 16 [Biffle] stayed in the middle of the racetrack like he was three-wide, and they ran out of room.”

Those three weren’t the only drivers to test sheet metal against concrete. Kyle Busch, Regan Smith and Michael McDowell all pancaked the right side of their cars.

“That’s one of the most action-packed practices I’ve seen in a long time,” Keselowski said.

He wasn’t certain why. But he did speculate that because the current Cup car will be replaced by a reengineered car in 2013: “The last race on any particular [style of] car seems to always have a lot of carnage. I’m very cognizant of that as well.”

Should events break that Johnson add a sixth Cup championship and move within one of the record shared by Richard Petty and the late Dale Earnhardt, it would be the second time in three years he had rallied from second in points in the finale.

Hamlin brought a narrow advantage to Homestead in 2010 but scraped with Biffle and spun out of contention within the first 100 miles.

The Keselowski-Johnson head-to-head showdown for the title has appeared destined since Keselowski outgunned Johnson in a one-two finish in the first of the 10 Chase for the Cup races.

That’s the way it has played out.