Former NASCAR chairman Bill France Jr. has been diagnosed with a virus, according to ESPN.com's Marty Smith. France is already showing signs of improvement after being admitted to Halifax Hospital in Daytona Beach, Fla. on Wednesday.
France, 73, is under the care of his personal physician. He has struggled breathing recently as a side effect of extensive radiation and chemotherapy treatments for cancer since 2000. He has been relying on a motorized scooter to get around.
"My health hasn't been too good," France said during media day before the Daytona 500 in February. "It's a good thing I [turned the sport over to others]. I have a hard time going to events. I'm sucking air all the time."
France turned the presidency of NASCAR over to Mike Helton in 2000 shortly after being diagnosed with cancer. He passed his duty as NASCAR chairman to his son, Brian, in 2003.
He kept his position as chairman of the board of International Speedway Corporation and vice chairman of NASCAR, but moved into a smaller office at NASCAR headquarters.
France said in February he'd cut back to two or three days a week in the office, jokingly adding, "Nobody listens to my ideas anymore."
France replaced his father, William Henry Getty France, as chairman of NASCAR in 1972. He was instrumental in making stock car racing the most popular motorsport in the country and moving it out of its Southern roots.
France suffered a mild heart attack in 1997 while in Japan for an exhibition race. He was diagnosed with cancer two years later, but never revealed what type.
ESPN.com NASCAR writers Marty Smith and David Newton contributed to this report.