DAYTONA BEACH, Fla. -- Brian Vickers is expected to replace injured driver Tony Stewart for the NASCAR season opener at Daytona International Speedway, a source with knowledge of the plans told ESPN's Bob Pockrass.
Stewart-Haas Racing has scheduled a Friday news conference to discuss its plans for the No. 14 Chevrolet. On Thursday, NASCAR Executive Vice President Steve O'Donnell said that Vickers has been cleared to race and that Stewart-Haas Racing has been given the OK to use a substitute driver in the exhibition Sprint Unlimited on Saturday. NASCAR, though, would not confirm that Vickers will be in the No. 14.
Vickers ran only two races last season before suffering a recurrence of blood clots. He can't compete when being treated for the clots because the blood thinners increase his risk of serious internal bleeding if he crashes.
Stewart is sidelined for the start of his final NASCAR season with a fractured vertebra. He was hurt riding an all-terrain vehicle in the desert in California last week.
Vickers is only expected to run at Daytona, which opens Friday ahead of the Feb. 21 season-opening Daytona 500. SHR is still looking at all of its options for beyond Daytona. Stewart is expected to race at some point this year.
Vickers has been sidelined four different times for health issues since 2010.
He missed the final five races of the 2013 season because he was placed on blood thinners to treat a blood clot in his right calf. He also missed 25 races during the 2010 season when clots were discovered in his legs and lungs.
During his 2010 absence, Vickers underwent a pair of procedures, one to close a hole in his heart and another to insert a stent into a vein in his left leg. He was private about the heart surgery and didn't address it until a month after the procedure.
Vickers was looking forward to last season, but surgery in December 2014 to repair a hole in his heart sidelined him for the first two races. He needed the surgery because his body was rejecting the artificial patch he received five years prior.
Vickers was able to run only two races before blood clots returned, and the need for blood thinners sidelined him the rest of the year.
Stewart's team has not released a timetable for his return from a burst fracture of his L1 vertebra, but doctors have told ESPN.com that it would likely take at least two or three months for his bone to heal. Stewart's doctors at OrthoCarolina declined a request to talk about his recovery.
"It will be important for him to engage in a sports type of rehab afterward, much as any other athlete would, to get his strength and flexibility back," said Mayo Clinic Dr. Paul Huddleston, an orthopedic surgeon and spine specialist. "With the bones, there's nothing he can do to speed up the two to three months it's going to take to heal."
The three-time Cup champion Stewart injured himself on a hard landing while riding a dune buggy in California. He had the surgery -- a fracture-stabilizing surgery, not a spinal fusion surgery -- Feb. 3 and plans to return when healthy to compete in his final Sprint Cup season.
Huddleston, who is not treating Stewart, said a typical patient after such surgery will be sore for six to eight weeks. He said Stewart risks an even more serious injury if he returns to racing before the bone is healed.
"The main concern someone who is close to the end of his career would be I don't want to compromise my long-term spine by coming back too soon and being re-injured again," Huddleston said.
"[Racing too early could cause] devastating spinal cord injury or it could compromise the metal implants that are put in there -- they could move in the spine and cause other damage, too.'"
Information from The Associated Press was used in this report.