Denny Hamlin's Sprint Cup title chances blew up yesterday when the right front tire of his Toyota exploded while he led the AMP Energy 500 at Talladega Superspeedway.

The former Chesterfield resident was taken to UAB-Birmingham Hospital after violently slamming his car into the wall on the back straightaway of the 2.66-mile tri-oval. Hamlin's car slid along the wall for nearly a quarter mile before stopping.

Hamlin, who entered Race 4 of the Chase for the Cup in 10th position, was taken from the racetrack on a stretcher. He complained of having a headache and ankle pain.

J.D. Gibbs, president of Joe Gibbs Racing, said Hamlin didn't appear to suffer any serious injuries as doctors examined him early last night. But hospital authorities held him for observation overnight.

Hamlin had managed to survive several close calls during the first 97 laps, including a nine-car melee on Lap 69. But as he hugged the apron coming out of Turn 2, with Kyle Busch shadowing his bumper, the tire blew.

Hamlin sat motionless for a while as track emergency personnel rushed to help him from the cockpit of his car.

"It was quite a shot, and [Hamlin] kind of hurt his ankle a little bit, but that should be OK," Gibbs said. "He's got a little headache, so they're just going to watch him. He's alert and doing well."

Hamlin was one of several drivers to experience tire problems -- including Brian Vickers, whose blown tire on Lap 69 triggered the nine-car crash.

"The tire went down and it was quite a shot," Gibbs said. "The good news is that [Hamlin] feels pretty good, but we're just going to take precautions and make sure he's OK. I talked to his family and just let them know what was going on."

Hamlin's crash, which left him with a 39th-place finish, didn't mathematically eliminate him from the Chase. But with six races remaining, he is 12th and the mountain he must climb seems too high.

Hamlin, who has qualified for the Chase in each of his three Cup seasons, is 335 points behind leader Jimmie Johnson. He is four points behind JGR teammate Kyle Busch, who led 23 laps before a Lap 174 accident left him 15th.

Goodyear officials said they were unable to determine what happened to Hamlin's tire. But Rick Heinrich, the tire manufacturer's product manager, said the constant bump-drafting could be one cause for Hamlin's tire problem.

"We can't say for sure what it is, but there was a ton of car contact that could have cause [the blown tire]," Heinrich said. "The [bump-drafting] is one of the possibilities."