CHARLOTTE, N.C. -- Sprint Cup driver Brian Vickers is expected to miss at least three months while undergoing treatment for blood clots, a source close to the situation told ESPN.com on Wednesday.
Red Bull Racing officials said they continue to wait for final recommendations from doctors and that details of Vickers' prognosis will be announced on Friday at Charlotte Motor Speedway, where the 26-year-old driver and general manager Jay Frye will appear at a news conference.
Casey Mears replaced Vickers last weekend at Dover International Speedway and finished 22nd. Mears again will drive the No. 83 in Saturday night's All-Star Race after Red Bull requested a driver change on Wednesday.
Red Bull officials said Vickers is responding well to treatment and continues to undergo tests in Charlotte, where he returned after being released from an undisclosed Washington, D.C., hospital on Friday night.
Vickers' former boss, Rick Hendrick, said Wednesday on his Amp Energy video conference that he has spoken to Vickers.
"We are good friends and I actually hooked him up with my doctor," Hendrick said on the chat. "He's doing well. They have to be careful. When you're dealing with blood clots you have to be extremely careful."
On the advice of the team's physician, Vickers -- who was complaining of chest pains -- entered a Washington hospital last Wednesday night. 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 at Dover, Red Bull officials contacted Mears upon Vickers' recommendation.
Team officials have not used a specific medical term in defining Vickers' 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, and two other doctors 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 the length of treatment ranges from three to six months to possibly a lifetime. He added that Vickers was lucky somebody sent him to the hospital so quickly.
"Most people die before they're diagnosed," Tapson said last week. "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."
Tapson said he was surprised more drivers don't develop clots because immobility is one of the contributing factors in clotting and drivers are confined to a tight space and have little motion for long periods of time.
He said the concern for Vickers is that if taken off blood thinners a clot could develop, move to the brain and be fatal. He said if left on blood thinners, any sort of accident on the track that causes trauma could result in the driver bleeding to death.
"Usually when we treat this we treat it with blood thinners," Tapson said. "Usually people on blood thinners, if it's what we call a reversible risk factor, you treat them for three months, sometimes six months.
"If you decide the patient has a continual list of blood clots then sometimes they take medicine for a lifetime. A lot may depend on what is his apparent risk. If they can't come up with any reason why he has a blood clot other than being a race car driver, then the option may be don't race cars anymore."
David Newton covers NASCAR for ESPN.com. He can be reached at email@example.com.