The three-time champion had surgery early Tuesday morning to repair a broken tibia and fibula in his right leg. A second surgery will be necessary. In the meantime, Stewart will remain hospitalized for observation.
I told someone to go get my phone or else I was going to get up and get it myself," Stewart said in a message posted on his website. "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."
Dr. Walt Beaver, the co-medical director at OrthoCarolina in Charlotte that heads up the clinic's NASCAR division, could not speak specifically to Stewart's injury. But he told ESPN.com that in general a broken tibia and fibula requires four to eight weeks before the patient can resume somewhat normal activities.
Stewart is 11th in points with only five races left in the regular season. Only the top 10 and two wild card drivers with the most wins between 11th and 20th make the Chase.
The 42-year-old Stewart already has been ruled out of Sunday's race at Watkins Glen even though no replacement driver has been named.
Tony Stewart taking unnecessary chances finally caught up to him when he suffered a broken leg in a sprint car crash Monday night, writes David Newton. Story
"It's just one of those things where every injury is a little different,'' Beaver said. "People heal differently, so it's very hard to put specifics on anything, but in general terms it's a 4-8 week process before people can get real active again.''
Beaver said injuries of this type typically require a rod being place in the leg to allow the broken bones to heal. He said a racecar driver could come back sooner than an athlete that depends on his legs for running, but there are other inherent risks.
Because a driver sits for a long period of time, Beaver said blood thinners likely would be prescribed to prevent clots. A driver isn't likely to be medically cleared while on blood thinners because that opens the risk of bleeding to death if involved in an injury.
Once the driver returns, Beaver said the risk of re-injuring the tibia during another wreck isn't great with a rod because the impact would have to be extremely hard to break the rod.
"Most of them when we put a rod in, then you really can get aggressive with rehab,'' Beaver said. "You can get back into activities within four, six to eight weeks, but reduced activities of weight bearing.''
Earnhardt Ganassi Racing developmental driver Kyle Larson, who competes in the Nationwide Series, was at the half-mile dirt track when Stewart crashed.
While he didn't see what happened, Larson understands the mentality that makes Stewart drive Sprint cars.
Mark Garrow has the details on Tony Stewart's Monday night sprint car wreck that resulted in Tony breaking his leg.
"It's real exciting,'' he said. "The cars are a lot of fun to drive. We both think the more we race the better we get. It's all relaxing to us to get away from the NASCAR stuff. That's why we do what we do.'' Larson said Stewart's injury and recent deaths in Sprint cars haven't given him pause to stop racing them as he tries to advance to the Sprint Cup level.
"I haven't been asked to stop,'' he said. "I don't think they'll ask me to stop. They'll just tell me to be smarter about the races I run. . . . It would be really tough to not race Sprint cars. It's just what we love to do.
"If something was to happen and I couldn't run Cup, I'd still have a blast racing Sprint Cars the rest of my life.''
The sprint car accident came a day after Stewart finished ninth in the NASCAR race at Pocono Raceway.
Stewart was leading the 30-lap feature in a 360 winged sprint car with five laps remaining when a lapped car spun in Turn 4 and collected Stewart and two others.
Race winner Brian Brown told The Des Moines Register that he saw the accident in front of him, turned left, hit an infield tire and kept going.
"It looked like he got into a lapped car," Brown told the Register. "When I got close, he was flipping cage down. I didn't really have time to watch and see what was going on.
"First and foremost, we're concerned about Tony and making sure he's all right. He's a huge asset to our sport, especially sprint car racing and an icon in the whole motorsports field. Anytime you see him wreck like that and then leave in an ambulance, it's never good. Hopefully he's OK. We weren't going to win that race. We were probably going to run third or fourth."
But Stewart's teammate, Ryan Newman is only 19 points behind him with a victory. If Newman finishes 23rd or better on Sunday with his Stewart-Haas Racing boss sidelined he could move into a wild card spot, depending on what Greg Biffle -- in 10th -- does with a victory.
Reigning champion Brad Keselowski (12th) and 2004 champion Kurt Busch (13th) are only two and six points behind Stewart without a victory, but this improves their playoff hopes.
It opens the door for drivers all the way back to Joey Logano in 17th place, 33 back and winless, with the top two drivers between 11th and 20th eligible for wild card spots with five races left in the regular season.
It's the third time Stewart has wrecked in the past month while competing in extracurricular races.
SportsNation Tony Stewart injured himself in a sprint car race. Is there any way he makes the Chase now? Cast your votes!
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 suffered a broken vertebra in her back.
Last Monday in Canada, 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 this past weekend when asked about his harrowing incident.
"You mortals have got to learn, you guys need to watch more sprint car videos and stuff," he said Friday at Pocono. "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."
Stewart gave an impassioned defense of sprint car racing in June following the death of good friend Jason Leffler, who was killed in an accident at Bridgeport Speedway in Swedesboro, N.J.
"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 racetrack. 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, of Palmyra, 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.
Newman and Clint Bowyer expressed support for Stewart on Twitter.