The Indianapolis 500 continues under green flag conditions on Lap 85 of 200 with Helio Castroneves having assumed the lead following the second pit stops of the afternoon.
Castroneves, a three-time Indy 500 winner, took the top position after then-leader Marco Andretti was slower off of pit road. Andretti, the grandson of 1969 winner Mario Andretti, has shown to have the fastest car as the race nears the halfway point.
Pole-sitter Ed Carpenter runs third, followed by Scott Dixon and Will Power. The early charger is Ryan Hunter-Reay, who went from his 19th starting position to sixth.
Defending champion Tony Kanaan will not defend his title following a mechanical failure that stalled his No. 10 Dallara-Chevrolet on pit road. Kanaan entered Sunday as the prerace favorite having set fast time in final practice Friday.
Graham Rahal was the first car out of the race due to an engine failure and will finish 33rd.
"Today was just not our day," Rahal said. "Really, it hasn't been his month."