A.J. Foyt will miss the final two races of the IndyCar season following surgery to treat a staph infection in his right knee.

The four-time Indianapolis 500 winner had surgery Aug. 10 on his artificial knee. He had a similar procedure in 2012 on his left knee.

This latest surgery required the removal of the prosthesis so an antibiotic-infused cement spacer could be inserted to clear the infection. It is expected to remain in place for six weeks, then Foyt will require another procedure to have a new artificial knee implanted.

The 80-year-old had a triple bypass last November that caused him to miss the first five races of the year.

Foyt Racing fields IndyCar entries for Takuma Sato and Jack Hawksworth.