Blood clots again sideline NASCAR driver Brian Vickers

FONTANA, Calif. (AP) - Brian Vickers has been sidelined again by blood clots that prevent him from safely driving a race car.

Vickers' third bout with blood clots was announced Friday by Michael Waltrip Racing. The team said the 31-year-old has been placed on blood thinners, which make it too dangerous for him to compete. If he is injured, the bleeding would be difficult if not impossible to stop.

"First and foremost our thoughts are with Brian and his family," said MWR founder and co-owner Michael Waltrip. "He isn't just our race car driver, he is our friend and we know the NASCAR community will continue to rally around Brian."

Brett Moffitt will return to the No. 55 Toyota this weekend at Auto Club Speedway as Vickers' replacement. Moffitt filled in once this season, at Atlanta, where he drove the car to an eighth-place finish.

"We are fortunate to have Brett Moffitt in our system and marveled at his great drive in Atlanta three weeks ago, so we know he can get the job done in the No. 55 this weekend," Waltrip said. "As this news is very fresh and the situation is very fluid, we can only plan for this weekend at this point."

The team did not immediately disclose when Vickers learned he had a recurrence of the blood clots.

Vickers missed the first two races of this year following offseason heart surgery to repair a patch on a hole in his heart that his body was rejecting. The heart issue was first discovered in 2010 when Vickers' was sidelined with his first bout with blood clots.

The blood clots caused Vickers to miss the final five races of the 2013 season because he was placed on blood thinners to treat a clot in his right calf. He also missed 25 races during the 2010 season when clots were discovered in his legs and lungs.

After his December heart surgery kept him out of the car two weeks, Vickers returned to racing two weeks ago. He was 15th at Las Vegas in his return, but was involved in a crash on the first lap at Phoenix last week and finished 41st.

"Thankfully, because I recognized the signs and symptoms, the doctors caught this early and I'm going to be ok," Vickers said in a statement. "I had finished my treatment for the clot I had in my leg back in 2013 and I haven't needed to be on a blood thinner for a clot in my leg or lung since. Now I won't be able to race because I'll need to be back on a blood thinner. I'm going to follow doctor's orders and do everything I need to do to get well."

Vickers also noted that his latest setback is occurring during "Blood Clot Awareness Month" and he was scheduled to help promote the issue this track with partner at Janssen Pharmaceuticals, one of his partners. He called the chance to raise awareness about the issue a "silver lining."

Moffitt, meanwhile, had been scheduled to drive this weekend for Front Row Motorsports, a ride he landed after his impressive stint for Vickers at Atlanta. Front Row needed a driver to step-in for David Ragan, who is replacing the injured Kyle Busch at Joe Gibbs Racing.

Moffitt was 37th at Las Vegas and 32nd at Phoenix for Front Row. The MWR development driver was using the Front Row opportunity to get seat time.