Petkovic, who only returned to the tour at this week's Stuttgart Grand Prix following more than three months out with a stress fracture of her back, is also doubtful for the London Olympics in July.
The 24-year-old turned her ankle while attempting a forehand in her second-round defeat by world number one Victoria Azarenka on Thursday.
The indoor crowd instantly fell deadly quiet, and Azarenka was left to look out for her opponent after the match.
"It's such a tough situation and the ankle right away blew up," said Azarenka.
"I hope she recovers soon because she is a great player. Andrea is one if the players who is tough mentally, she is a great fighter."