During the closing minutes of the first practice, scheduled late in the afternoon, a five-car crash occurred when Tony Stewart got into the rear of Kurt Busch and then turned him around coming out of turn three. Allmendinger, Keselowski and Kyle Busch were also caught up in the incident.
"I was pushing the 51 car [Kurt Busch], and he had to move a little bit, but I'm still the one pushing him, so I'm responsible for it," Stewart said.
Kurt Busch, making his debut in the No.51 Chevrolet for Phoenix Racing, will use a backup car.
"It was just a deal where Tony was trying to help, and we were just trying to learn the draft," he said. "A couple of slow cars were emerging in front of us, and I slid up to go around them, and I thought it was smooth, but I got turned around."
Allmendinger, Keselowski and Kyle Busch have also switched to their backup cars.
Stewart's No.14 team were hopeful to have his primary car repaired in time for the race.
Jeff Gordon managed to avoid the incident but did suffer minor damage to his car, which was quickly repaired.
Matt Kenseth led the way in the opening practice with a lap around the 2.5- mile superspeedway at 201.762 m.p.h.
The second and final practice, held in the evening, was curtailed due to rain. Just 12 drivers managed to turn a handful of laps in the opening minutes before the inclement weather forced NASCAR officials to halt action on the track.
Saturday's Budweiser Shootout is scheduled to start at 8:10 p.m. (et).