Dale Earnhardt Jr. has concussion

CONCORD, N.C. -- Dale Earnhardt Jr. will miss the next two
races with his second concussion in the past six weeks, all but ending the championship chances of NASCAR's most popular driver.

The first concussion, suffered in a crash during an Aug. 29 tire test at Kansas, went undiagnosed until Wednesday, when Earnhardt
was examined in Charlotte because of lingering effects from Sunday's crash at Talladega.

Earnhardt said he didn't report symptoms he was having after the Kansas crash for fear of being taken out of the car for the start of the Chase for the Cup.

"I remember everything about that accident, everything after that accident," Earnhardt said. "But I knew I didn't feel ... you know your body and how your mind works. I knew something was just not quite right. I decided to push through and work through it. I had concussions before and knew exactly kind of what I was dealing with. I felt pretty good after a week or two, definitely 80 to 90 percent after the Chase started. By the time I got to Talladega I felt 100 percent, really good."

Hendrick Motorsports said Earnhardt will sit out races at Charlotte and Kansas; Regan Smith will replace him in the No. 88 Chevrolet.

A source with knowledge of Earnhardt's business told ESPN that his salary from Hendrick to drive the car will not be affected by his missed races.
Also, the money paid by his primary sponsors (Amp Energy this weekend and National Guard at Kansas) will not be affected in his absence.

Earnhardt, who celebrated his 38th birthday Wednesday, was injured in a 25-car, last-lap accident at Talladega. Because
he was able to drive his car away from the accident -- teammate
Jimmie Johnson even caught a lift on the window back to the garage -- Earnhardt was not required to go to the care center for an
examination at the time.

Immediately after the race, he called restrictor-plate racing "bloodthirsty" and said he no longer had any desire to compete at
Daytona and Talladega.

During the Goodyear test at Kansas, Earnhardt's car struck the wall with enormous force after his right front tire failed, an accident driver
Brad Keselowski tweeted about moments afterward.

Earnhardt said data confirmed the hit at Kansas was 40 Gs, compared to 20 Gs at Talladega. He said persistent headaches after the Talladega crash caused him to seek out Dr. Jerry Petty, his personal physician who also is the physician for NASCAR.

Earnhardt said results from tests taken Tuesday and an MRI administered Wednesday indicated there was no damage to his brain. But because the headaches persisted, Petty made the decision to rule him out for two weeks.

"I trust his opinion," Earnhardt said. "That's why I went to see him. He's been a good friend of mine for a long time, helped me through a lot of injuries before. I believe when he tells me I don't need to be in the car."

Petty said he doesn't anticipate any issues that would prevent Earnhardt from being cleared after sitting out two races.

"He had no amnesia after either incident, which is very
important," Petty said. "We'll want to give him four, five days without a headache," and then they'll try to invoke a headache to
see how he reacts before clearing him to race.

Said Earnhardt: "I feel perfectly fine, but I don't want to keep getting hit in the head."

Earnhardt earlier this season snapped a 143-race winless streak dating to 2008, and many believed he was in the best position in
years to finally win his first Sprint Cup Series championship. But
he had a mediocre start to the Chase and left Talladega ranked 11th in the field.

Although he's mathematically still in the running in the 12-driver Chase race, by sitting out the next two races he'll most certainly finish last.

Earnhardt's streak of 461 consecutive starts -- the fifth-longest active streak in the Sprint Cup Series -- also will end.

Keselowski was among the drivers reacting via Twitter. "Might be late to the party, but I'm absolutely floored to hear about dale jr. Not racing this weekend. Concussions are no joke...," Keselowski tweeted.

NASCAR strengthened its commitment to keeping drivers with concussions off the track in 2002, in part because Earnhardt
admitted he was unable to fully concentrate or communicate with his crew chief after an accident at California. He self-diagnosed
himself with a concussion, which he revealed weeks later.

NASCAR then said doctors at infield care centers could require drivers to undergo CT scans or MRIs if they suspected a concussion.
Clearance to race after suffering a concussion is not given until
after a driver obtains a medical release.

Robin Pemberton, NASCAR's vice president for competition, said it would be a "stretch" to say the injury gives more credence to Earnhardt's plea for changes at Talladega.

"We work on safety every day," Pemberton told ESPN.com. "People complain about different races all the time, whether it's restrictor plate or someplace else they don't think we need to be racing at. We work on things. We make the safest car possible and we do what's right for the garage area and the fans and we try to balance that ecosystem.

"It could have happened anywhere on any racetrack we run at ... whether it's at testing or an event, these things can happen."

Pemberton said the governing body did not take offense to Earnhardt's "bloodthirsty" comment about the racing at Talladega.

"We get comments after every race," he said. "That's just part of it. I don't think good, better or different about it. People have opinions. We don't always agree. That's OK."

Nationwide Series driver Eric McClure missed six weeks this season because of lingering effects of a concussion suffered at Talladega. McClure said the concussion he suffered in the May 5 race was the third of his career, one of the main reasons his doctors and NASCAR officials made him sit out for an extended period of time.

"There's not really a set timetable for those things and that's been the challenging thing," McClure said after his June return. "That's what kept me from coming back was the lingering symptoms. I really felt . . . after the first two weeks of being away from the track, and having total brain rest, that I was ready. But (my doctor) felt like we needed to wait, and I respect that opinion."

Pemberton on Thursday praised everyone involved for being proactive about head injuries, compared to years ago, when drivers who had concussions still would compete. He said data recorders and other advances have helped make everyone more aware of the significance of the impact drivers absorb in wrecks.

"It's like anything," Pemberton told ESPN.com. "We get better as time goes on. You learn from things and you work on it and you make things better. That's what we do."

ESPN analyst Ricky Craven, whose Sprint Cup career was affected by post-concussion syndrome from a 1997 crash, agreed with Pemberton that Earnhardt's injury is not a mandate for change at Talladega. From Craven's understanding, he believes Earnhardt's concussion is related to the big hit in August at Kansas.

"I don't think it has any effect on any of that," Craven said. "My focus on this would be more along the lines of Dale Jr. showing the responsibility to handle it or manage it."

Information from The Associated Press, ESPN.com senior motorsports writer David Newton and ESPN.com sports business reporter Darren Rovell was used in this report.