Reid Spencer
Sporting News NASCAR Wire Service

Brian Vickers' Red Bull Racing team discovered a problem with the engine in the pole-winning No. 83 Toyota after Friday's qualifying session and opted to change power plants, NASCAR officials confirmed Friday night. As a result, Vickers will start from the rear of the field in Sunday's Auto Club 500 Sprint Cup Series race.

Vickers is still credited with the pole, the sixth of his career, and retains the first choice of pit stalls. NASCAR requires any car that undergoes an engine change between qualifying and the race to start from the back. Vickers will have a chance to shake down the new engine during final Cup practice, scheduled for 5:15 p.m. ET Saturday.

When Vickers drops to the rear on Sunday, each of the cars on the inside row each will move forward, putting third-place qualifier Jamie McMurray in the pole position for the start of the race.