Kurt Busch spins through grass at end of Happy Hour

Kurt Busch posted the third-fastest time in the Happy Hour final practice session for the Sprint Cup Series on Saturday at Kansas Speedway, after qualifying sixth on Friday night.

While his speed was impressive, Stewart-Haas Racing announced he'll go to a backup car when the green flag drops on Sunday for the Hollywood Casino 400, after cutting down a tire and spinning across the infield, burying his splitter in mud and grass.

As the final seconds ticked off of the practice clock, Busch exited Turn 4 and the back of the car spun out from under him, sending him nose-first into the grass.

Busch will start from the back of the field on Sunday. His best finish at Kansas came in 2013 when he placed second, after starting from the back of the pack.