Brad Keselowski got some help on the last day of practice for NASCAR’s Sprint Cup season finale at Homestead-Miami (Fla.) Speedway. Pole sitter Joey Logano was involved in a three-car accident during the first of two practice sessions Saturday, switched to a backup car and will start from the rear of the field today. That will move Keselowski, who had qualified third, to the front when the green flag drops today. Marcos Ambrose will start on the outside. And if Keselowski leads the first lap, he will extend his points lead from 20 to 21 in the 400-mile race. He needs to finish 15th or better to clinch the title, which would be the first for longtime NASCAR team owner Roger Penske. Fellow title contender Jimmie Johnson will start 10th in the finale. Keselowski was faster than Johnson in practice Saturday. Keselowski turned the faster lap and edged Johnson with a better 10-lap average.