DOVER, Del. -- Brian Vickers has multiple blood clots in his veins that will keep him out of Sunday's Sprint Cup race at Dover International Speedway and off the track for the near future.
Jay Frye, the general manager of Red Bull Racing, confirmed Vickers' medical condition Friday at Dover.
On the advice of the team's physician, Vickers -- who was complaining of chest pains -- entered an undisclosed hospital Wednesday night in Washington, D.C. It was discovered several clots had developed in his veins, including one in or around his lungs and one in his legs.
Vickers was immediately put on high dosages of medication to thin his blood and break up the clots. When it became apparent he would not be able to drive this weekend, Red Bull officials contacted Casey Mears as Vickers' replacement.
"Brian is a good friend of mine," said Mears, who qualified 39th. "I hate to see him going through what he's going through. [But] it's fun to be at the racetrack and knowing we're running on Sunday."
Frye said there is no timetable for Vickers' return to the track.
"In our press release [Thursday] we said this is a minor setback," Frye said. "It is a minor setback in a young man's life and career. Obviously it is a major setback for the race team and this weekend. As far as a timetable for his return, we're not sure."
Missing the race likely will end any chance the 26-year-old Vickers has of making the 12-driver chase for the championship for the second straight season. He is 20th in points, 160 points out of the 12th and final spot for the 10-race playoff. By missing a race, he will lose at least 156 points to the 12th spot and up to 190 to the race winner.
"He's a long-term player with Red Bull Racing," Frye said. "Our main concern is his health."
Frye, without being specific, said some of the things Vickers does as a driver on a daily basis could have contributed to the condition. He discounted the condition had anything to do with Vickers breathing a heavy dose of carbon monoxide inside his car after a recent incident at Texas.
"At Texas we had damage," Frye said. "We had to park the car early because of stuff going on inside the cockpit. In conversations with Brian, that never was mentioned."
Frye said Vickers' doctors have not used a specific medical term in defining the driver's condition. Dr. Victor Tapson, an associate professor for the division of pulmonary medicine at Duke University and co-chair of the Council for Leadership on Thrombosis Awareness and Management, said Vickers' symptoms are a sign of deep vein thrombosis with a pulmonary embolism.
Tapson, who is not treating Vickers, described the driver's condition as life-threatening and said length of treatment ranges from three months to a lifetime.
"Most people die before they're diagnosed," Tapson said Friday. "Most people that die aren't even expecting it. Once it's diagnosed you're certainly not out of the woods, but you're ahead of the game."
Frye said there was a chance Vickers could be released from the hospital as early as Friday, adding that the uncertainty made it necessary for the team to move forward with Mears in the No. 83 car.
He indicated that having Vickers take the first lap on Sunday -- which would allow the driver to keep any points the car earned in the race -- was not an option.
Tapson said he was surprised more drivers don't develop clots because immobility is one of the contributing factors and drivers are confined to a tight space with little motion for long periods of time.
"If I have a patient that has blood clots before and he's on blood thinners and he is driving to New York seven or eight hours, we'll tell him to take that preventative shot before he goes," Tapson said. "If he comes off the blood thinner then another clot could form. It's a concern in a race car driver, for sure."
Jimmie Johnson said Friday that Vickers sounded like his usual self when they spoke Thursday night.
"There's still a lot of question marks and concerns and trying to understand just what in the world is going on," Johnson said. "Until they can find out what's going on, there's a lot of worry and concern."
Frye did not sound optimistic that Vickers would be in the car for next week's Sprint All-Star Race at Charlotte. He was unsure if another driver could drive the car in the nonpoints event that Vickers qualified for by winning at Michigan last season.
"There's really no hurry for him to get out," Frye said of Vickers. "Our real focus is to get through the weekend and then evaluate. We'll know more next week. There are questions about the All-Star Race. Are we in or out? I am trying to get clarification."
NASCAR doctors must give Vickers clearance before he can race again. Spokesman Ramsey Poston said the governing body is working in conjunction with the team.
David Newton covers NASCAR for ESPN.com.