There are seven others who can earn year-end bonuses from INDYCAR by finishing in the top five of the standings.
Simon Pagenaud, driver of the No. 77 Schmidt Hamilton HP Motorsports car, is third in standings entering the 250-lap season finale at 8 p.m. (ET) on NBC Sports Network. Depending on results, he could overtake Castroneves for second and claim the $250,000 bonus. The third-place driver will earn $175,000, with Justin Wilson of Dale Coyne Racing, Ryan Hunter-Reay and Marco Andretti of Andretti Autosport and Will Power of Team Penske also in contention.
All those drivers plus James Hinchcliffe of Andretti Autosport and Charlie Kimball of Novo Nordisk Chip Ganassi Racing are eligible for the fourth-place prize of $125,000. Fifth place pays a $75,000 bonus.
"We have been dominant in the 500-mile races and have led a lot of laps, but Fontana is about leading the right lap, and that's what we need to do," said Andretti, who earned the pole for the 2012 race. "I'd really like to end the season with a 'W' for the Dr Pepper team. Auto Club Speedway is a tricky place to get right with the seams, but will be rewarding if we do."
Additionally, the manufacturer championship will be decided in the race as Chevrolet and Honda are tied in points. Both have nine victories.