Bizarre multi-car wreck halts NASCAR Sprint Cup practice

Less than four minutes into the session and with rain imminent, Danica Patrick came off Turn 4 and the back end of her No. 10 Chevrolet burst into flames and began dropping rear-end oil.

Both Tony Stewart and Jamie McMurray both got caught in the oil and slammed into the wall before coming at a rest on the backstretch.

“I saw flames coming out before it hit,” one of Patrick’s crew members reported over the team radio. Then, the attention turned to Stewart, who underwent back surgery in January. “The window net is down. He’s slow to get out.”

All three going to backups

Patrick, Stewart and McMurray will all have to go to backup cars for Sunday’s AAA 400. All three drivers were treated and released from the care center. McMurray was holding his left elbow after getting out of the car.

“It’s not something you commonly see,” Patrick said after exiting the infield care center. “I don’t know if it was human error or bad luck. Any time you worry about Tony, just making sure he’s OK after everything he’s gone through.”

Stewart-Haas Racing competitor director, Greg Zipadelli, said it appeared the No. 10 car suffered a gear failure.

“I don’t know what brings it. They’re all brand new gears,” he said. “All the cars have the same gears from the same manufacturer. We’ve won this gear at other places. It’s too early to tell the reason.”

Kurt Busch catches his own issue

Zipadelli also said Kurt Busch’s No. 41 had an issue as well but he was able to return to the garage before it became an issue. All SHR cars were changing gears after the incident.

"I was feeling something all along with the rear gear and drive train. ... It was feeling weird, so I got lucky," Kurt Busch said after the incident.

Stewart and McMurray declined interviews at care center. Stewart went directly to his motorcoach.

When the practice session was red-flagged, only 20 cars had posted speeds. The top five were Denny Hamlin, Carl Edwards, Martin Truex Jr., Austin Dillon and Kevin Harvick.