DOVER, Del — Casey Mears normally is the driver watching Cup races on TV.

He'll be in the car at Dover International Speedway while Brian Vickers sits this one out.

Mears was needed in a pinch this weekend because Vickers, his friend and Red Bull Racing driver, is hospitalized with blood clots in his veins around his lungs and in his legs.

His Chase for the championship chances are all but gone, but he has more pressing concerns.

"Dealing with that and doing that right is way more important than being here at the track right now," Mears said Friday. "It's never fun to be watching races at home. I'm sure that will wear on him."

Mears knows how Vickers feels.

Mears qualified for only two races this season and has bounced around after sponsorship cutbacks cost him his job at Richard Childress Racing. He was on standby after Denny Hamlin had surgery to repair a torn ACL, and he'll drive week-to-week for Tommy Baldwin's No. 36 car as long as Baldwin can find funding for each race.

He drove the first two months of the season for underfunded Keyed-Up Motorsports.

"It's been crazy, it really has," Mears said. "Obviously, not what I want. I want something solid and I want to run all season. At the same time, there's been parts of it that have been fun. It's enlightened me a lot on what other guys are doing, different teams are doing. In a lot of ways, I learned a lot this year."

Red Bull Racing general manager Jay Frye said Vickers is on medication and was hopeful of being released from the hospital Friday, but could remain there a few more days. Frye said there is "no timetable" for Vickers' return.

"He's got great reason for optimism that everything's going to be fine," Frye said.

Frye says Vickers complained of discomfort in his chest and went to a hospital in Washington. He says the team is not sure what caused the clots.

The 26-year-old Vickers is in his seventh full season racing in NASCAR's Sprint Cup Series. He has two career Cup wins and made the 12-driver Chase for the championship last season. He's currently ranked 20th in the standings. Missing a start almost certainly will make it impossible for Vickers to make the Chase this season.

"It is a minor setback in a young man's life and career," Frye said. "Obviously, it's a major setback for our race team this weekend."

Jimmie Johnson said 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 said Mears will drivethe No. 83 Toyota for RBR for as long as the team needs him.