Tony Stewart suffered his first serious hit since his return from a back injury during a three-car wreck at practice Friday at Dover International Speedway.

Danica Patrick's No. 10 dumped oil on the track, spun and the rear of her Chevrolet burst into flames. Stewart, her Stewart-Haas Racing teammate, was behind her and the No. 14 hit the oil and smacked the wall.

Jamie McMurray hit an unprotected portion of the wall. He held his left elbow as he walked out of the medical center.

Stewart told his team the hit hurt him. He missed the first eight races of the season with a fractured vertebra suffered in a January all-terrain vehicle accident.

Kurt Busch, a third SHR driver, complained of issues in his Chevy and pulled off the track.