Dale Earnhardt Jr. was cleared Tuesday for this weekend’s race at Martinsville Speedway after missing the last two weeks to recover from two concussions. NASCAR’s most popular driver was examined by neurosurgeon Jerry Petty a day after he ran 123 laps at half-mile Gresham Motorsports Park in Jefferson, Ga. Petty kept Earnhardt sidelined after the driver was complaining of a lingering headache following a 25-car accident on the last lap of the Oct. 7 race at Talladega. Petty diagnosed Earnhardt with a concussion, and said Earnhardt also suffered one in an Aug. 29 crash during a tire test at Kansas that went untreated. It snapped Earnhardt’s streak of 461 straight starts, the fifth-longest active streak in the Sprint Cup Series, and ended his shot at winning the Chase for the Sprint Cup championship.