CONCORD, N.C. -- Kyle Busch said it was pneumonia that forced him to give way to a backup driver in last weekend's Sprint Cup Series and Nationwide Series races at California.
But the Nationwide point leader said he's strong enough that he won't need relief in either this weekend at Lowe's Motor Speedway.
"I'm still having side affects, still being on the medicine still throws your head for a little loop until you get out there for a few laps,'' Busch said after qualifying for Friday night's Nationwide race. "You just have to get reoriented and have a clean focus on it all.''
Busch gave way to Joe Gibbs Racing teammate Denny Hamlin 39 laps into last weekend's Nationwide race. Hamlin finished 31st after a late-race crash, allowing Carl Edwards to cut Busch's point lead from 245 to 155.
David Gilliland relieved Busch early in the Cup race and finished 30th.
"I never had to do it before in my life,'' said Busch, who began the weekend with a cold before it turned first to the flu and then pneumonia. "It was pretty hard to do. It's something you don't ever want to have to do, but when you get in the car and get hot and your fever starts to rise and you get dizzy, it's just not safe being out there.
"I never got to that point of being dizzy, but I knew if I stayed in, I would.''
David Newton covers NASCAR for ESPN.com. He can be reached at firstname.lastname@example.org.