Earnhardt, who captured the pole three days ago, was forced to go to a backup car and will have to start from the back of the pack in NASCAR's most prestigious race.
The 36-year-old Earnhardt was drafting, running in back of team mate Jimmie Johnson, when they approached some slower traffic.
Johnson, the reigning five-time NASCAR Sprint Cup champion, took his foot off the gas to avoid a collision and Earnhardt was hit from behind by the car of Martin Truex Jr. Johnson's car was untouched.
"Me and Jimmie had to check up (off the throttle) and I got hit from behind there," Earnhardt told reporters.
"The guys on the inside looked like they were going to stay low and then they started kind of creeping up so Jimmie lifted. And he about wrecked.
"I got off the gas and there were a couple of guys coming behind me. Truex and a couple other guys just didn't have a chance."
Truex told reporters, "We came up on some slower cars and it looked like they just came up in front of the 48 (Johnson) and 88 (Earnhardt).
"When they checked up, I checked up, and I was being pushed."
Earnhardt did not blame Truex but did chide the slower drivers.
"You got to pay attention out there, man," he said. "I mean if you're going to come out here and race, you need to pay attention."
Although Earnhardt was uninjured he had to withdraw his car. Under NASCAR rules if you substitute a car for a qualified one you must start at the rear of the 43-car grid.
Earnhardt's backup car did not have an engine and other necessary equipment making it unlikely that he would get back on the track for the final practice session.
(Editing by Steve Ginsburg)