Renault's Russian driver was reprimanded by stewards and handed a five-place penalty on the starting grid for the Indian Formula One Grand Prix after causing a collision in Korea on Sunday.
Petrov rammed into the Mercedes of seven-times world champion Michael Schumacher at the entry to turn three on the 16th of the 55 laps, putting both out of the race.
The Russian apologised to the German afterwards.
"I tried to defend my position from (Ferrari's) Fernando (Alonso) but I was in the braking zone on the dirty side of the track which meant I locked my wheels and hit Michael," said Petrov.
"I was focused on my battle with Fernando...we both braked too late as he missed the corner too.
"I apologise to Michael. It was not his fault, it was absolutely my fault."
Schumacher said he had not seen Petrov before the impact.
"I was just suddenly spun into a direction I had not intended to go and then I saw my rear wing hanging off. It was unfortunate but these things happen when you fight hard, that's racing."
The inaugural Indian Grand Prix is on October 30.