CONCORD, N.C. (AP) Dale Earnhardt Jr. has a concussion and will sit out the next two Sprint Cup races at Charlotte and Kansas. The injury ends NASCAR’s most popular driver’s championship chances this season. Hendrick Motorsports says Earnhardt Jr. was diagnosed Wednesday afternoon. He sustained the concussion in the 25-car pileup on the last lap of Sunday’s race at Talladega. Regan Smith will replace Earnhardt Jr. in the No. 88 Chevrolet in the next two events.