KANNAPOLIS, N.C. — Tony Stewart told anyone who would listen why he continued racing anywhere, anytime, regardless of purse or crowd or car.

Even after he flipped five times last week, Stewart was quick to offer a stout defense for his short-track weeknight racing while some questioned if his extracurricular racing was putting his championship chances in NASCAR at risk.

Well, his championship chances are officially over for this season.

The three-time NASCAR champion broke his right leg Monday night at Southern Iowa Speedway in Oskaloosa, where he flipped his 360 winged sprint car while leading with five laps remaining in the 30-lap feature. He had surgery Tuesday on the upper and lower parts of his leg, and Stewart-Haas Racing said he'll need a second surgery.

He remained hospitalized and there was no timetable for his return to racing. Max Papis was tabbed to replace Stewart this weekend in the No. 14 Chevrolet at Watkins Glen, where Stewart is a five-time winner and his streak of 521 consecutive starts will end.

"I told someone to go get my phone or else I was going to get up and get it myself," Stewart said Tuesday in a Facebook post. "Finally got reconnected to the world and just want to say thank you for all the prayers and well wishes. My team will remain strong and I will be back."

The 42-year-old Stewart has wrecked three times in the last month in extracurricular racing, and the latest came a day after he finished ninth at Pocono in a NASCAR event to position himself 11th in the Sprint Cup standings with five races remaining to set the Chase for the championship field.

But Stewart had long refused to slow down his sprint car racing schedule, and passionately defended it following the June death of friend Jason Leffler in an accident at Bridgeport Speedway in Swedesboro, N.J.

He was just as impassioned last Friday at Pocono when asked about his accident last week in Canada in which Stewart flipped a sprint car five times.

His childhood hero, four-time Indianapolis 500 winner A.J. Foyt, defended Stewart on Tuesday for sticking to his passion and being a true "racer."

"He ain't no prima donna and life is short, and we don't know how we are going to die or what's going to happen," Foyt said in a telephone interview with The Associated Press. "I just hate to see anybody badmouth Tony for anything he's doing, and if they are, they are just jealous. People saying he's putting his businesses at risk? I had three dealerships, people respected me."

"If they are worrying about their jobs and him getting hurt, what's to say he won't have a heart attack tomorrow and die?" Foyt said. "He might die and it might not be from racing. I had business and I still raced. I always said I am going to continue racing until I don't want to race anymore and he's the same way."

Stewart took responsibility for triggering a roughly 10-car accident at Canandaigua (N.Y.) Motorsports Park on July 16 in which 19-year-old Alysha Ruggles injured her back.

Last week, in a sprint car race at Ohsweken Speedway in Ontario, Stewart rolled his car five times but walked away. He stayed at the track to compete in the World of Outlaws race the next night and bristled at the NASCAR event at Pocono Raceway when asked about his harrowing incident in Canada.

"You mortals have got to learn, you guys need to watch more sprint car videos and stuff," he said Friday. "It was not a big deal. It's starting to get annoying this week about that. That was just an average sprint car wreck. When they wreck, they get upside down like that."

Following Leffler's death, Stewart defended track and sprint car safety.

"I'd be grateful if you guys would understand that what happened this week wasn't because somebody didn't do something right with the race track. It was an accident. Just like if you go out and there's a car crash. It's an accident," Stewart said days after Leffler's death. "Nobody as a track owner wants to go through what happened, but it's not due to a lack of effort on their part to try to make their facilities as safe as possible under the conditions they have."

On Sunday, veteran sprint car driver Kramer Williamson died from injuries suffered during a qualifying race at Lincoln Speedway in central Pennsylvania. Williamson, 63, was pronounced dead at York Hospital from serious injuries suffered in a crash that occurred Saturday night during the United Racing Company 358/360 Sprint Car Challenge.

Although it sounds cliche, Foyt believes racers want to go out doing what they love.

"Tony is a true racer," Foyt said. "That's one thing I respect about him. A lot of them people go to NASCAR and become a kingpin in one type of car. Jeff Gordon and Kasey Kahne, they all were sprint car and midget cars drivers first, like Tony, and Tony still is a sprint car driver and it's a shame he got hurt. But I don't see where someone can condemn him for it."

Gordon said it became too difficult for him to juggle various series when he went full-time NASCAR in 1991.

"I was racing Nationwide and Silver Crown and midget sprint cars and it was cool and exciting and fun and everything, but when I got full-time in the Nationwide Series, I just wanted to focus on that," Gordon said. "I tried to do Nationwide and Cup a couple times and I didn't really enjoy going back and forth, but my hats off to the guys that do that and enjoy it and do well with it.

"Sprint cars are to me some of the most exciting and fun race cars there are to drive. Anything that you do, you could put yourself at risk, so I think that he knows the risks versus the rewards and chooses to do that and I think that's awesome and he certainly is very impressive when he gets in them how competitive he is. I certainly look up to him in that way because I raced those guys in sprint cars and know how difficult that is."