Four-time IndyCar champion Dario Franchitti announced Thursday he will no longercompete in auto racing because of injuries suffered in an Oct. 6 crash.

The Chip Ganassi Racing driver suffered a broken spine, broken right ankle and concussion in a crash at the Houston Grand Prix. The 40-year-old underwent two sugeries on his ankle and recently returned to Scotland to recover.

"Racing has been my life for over 30 years, and it's really tough to think that the driving side is now over," Franchitti said, according to the Associated Press. 

The three-time Indianapolis 500 winner said doctors told him it would be too dangerous for him to keep racing because of injuries sustained in the crash.

"Since my racing accident in Houston, I have been in the expert care of some of the leading doctors and nurses, all of whom have made my health, my safety and my recovery their top priority. I am eternally grateful for the medical care I have received over the last several weeks. I'd also like to thank my family and friends for their unbelievable support."

Dario Franchitti kept racing after the death of best friend Greg Moore. He continued on following the death of former teammate Dan Wheldon. He was eager to drive into his early 40s.

"One month removed from the crash and based upon the expert advice of the doctors who have treated and assessed my head and spinal injuries post accident, it is their best medical opinion that I must stop racing. They have made it very clear that the risks involved in further racing are too great and could be detrimental to my long term well-being. Based on this medical advice, I have no choice but to stop."

Franchitti, 40, and his team were looking forward to his return in 2014, when Ganassi is welcoming 2013 Indianapolis 500 winner Tony Kanaan to the game that already includes three-time and reigning IndyCar champion Scott Dixon.

Word of Franchitti's decision spread quickly and drivers who never raced against him reacted with sadness.

"I think to have him around and on the circuit is far better than him going an injuring himself again against doctor's advice," said Nigel Mansell, who was at Circuit of the Americas in Austin, Texas, for this weekend's Formula One race.

Franchitti 31 victories are tied for eighth on the all-time list, and his 33 poles are sixth.