SONOMA, Calif. -- Driver Will Power of Team Penske broke two vertebrae in his lower back and sustained a concussion Saturday after crashing into Nelson Philippe of Conquest Racing during a practice session for the Indy Grand Prix of Sonoma.
Philippe also sustained a concussion along with an open fracture to his left foot that required surgery.
The 28-year-old Power, the former road course specialist who finished fifth in this year's Indianapolis 500, crashed into Philippe coming out of a blind corner at Infineon Raceway. He was scheduled for an MRI exam later Saturday, but IndyCar officials didn't expect any further updates on his status until Sunday.
Power, Penske's third driver, was airlifted to nearby Santa Rosa Memorial Hospital. Philippe was taken by ambulance to the same hospital, where he was undergoing surgery on his foot.
IndyCar officials said both drivers were reported to be awake and alert and were to be hospitalized at least overnight. They each withdrew from the race, meaning no new driver will fill the seat.
Philippe lost control at the top of the hill on Turn 3A, and the front end of his car was initially clipped by E.J. Viso. Power arrived moments later and couldn't avoid an ugly crash, T-boning Philippe's car.
"It's pretty serious," said Power's Penske teammate Ryan Briscoe, who qualified second Saturday. "We definitely need to look at the safety over here and what can be done differently with spotting or whatever to Turn 3A. It's a dangerous corner. So, definitely wishing him the best at the moment."
Coming into this event, Power was 16th on the season points list with 209.
This is a big blow -- and scare -- for Power, who earned his first IndyCar win July 26 at Edmonton after starting from the pole and leading 90 of 95 laps.
Dario Franchitti, who won the pole Saturday, called it a "horrible accident."
Power moved to Team Penske for his second season in IndyCar, impressing owner Roger Penske with his professionalism and willingness to do whatever was needed for the team.
Power filled in while Penske Racing star Helio Castroneves went to trial on tax-evasion charges. After Castroneves returned, Penske rewarded him with a part-time ride. Power was scheduled to run one more race for Penske this year, at Homestead at the end of the season.
Power, who grew up in Australia watching his father race Formula 2 on the weekends, drove the No. 3 Penske car to a sixth-place finish in the season opener at St. Petersburg and followed that by finishing second at Long Beach.
Power spent two-plus seasons in the Champ Car World Series before the merger with IndyCar last year. He struggled to find any consistency while driving for KV Racing Technology, finishing 12th in points despite having trouble at times on the ovals.
Philippe, a Frenchman, is an IndyCar rookie.
Doctors have access to a computerized test called "ImPACT" on site that can help them determine the severity of the concussions. The test was developed by the Sports Concussion Program at the University of Pittsburgh Medical Center. It puts the brain to work and derives data about points of trauma -- measuring attention, memory, processing speed and reaction time.