The Serbian former world number one was forced to quit with severe pain in her right arm when trailing 2-5 against Russia's Maria Sharapova in Tokyo Saturday, putting her bid to defend the China Open in jeopardy.
"My wrist and the whole arm this moment is in pain, it's swollen," she said before leaving for China.
"So I don't know how it will recover, if it will recover by the time I begin over there (Beijing)," she said.
Jankovic earlier said her goal for this season was to earn her ticket to the 4.55-million-dollar championships to be held in Doha later this month, involving the eight top players in 2009.
"My goal is to make it to the championships," said Jankovic, currently in ninth position. "That's what I am trying this moment."
For the China Open, which started Saturday, she received a first-round bye and will face the winner of the clash between Peng Shuai of China and Virginie Razzano of France.
The 24-year-old Jankovic has had a difficult season on and off the court with the death of her grandmother, illness for her mother and having to adjust to working with a new coach.
She was ousted in the fourth round at both the Australian Open and the French Open and crashed out of Wimbledon in a third round shock to US teen sensation Melanie Oudin.
Jankovic only reached the second round of the US Open, during which she learned about her grandmother's death.
This season has a disappointment after the highs of 2008, when she soared to world number one, bagged four titles and reached her first Grand Slam final at the US Open.
"I can just do what I can do in the next couple of tournaments, and try to finish the year in the best possible way, and hopefully start 2010 better than I began this year, which was very difficult for me," she said.
Jankovic became aware of her new injury during her semi-final match Friday afternoon against Li Na of China at the hard-court Ariake Colosseum but went on to win the match with a bandage covering her right upper arm.
After the final against Sharapova, Jankovic emerged with another bandage wrapped around her right wrist.
"I started to feel pain in my shoulder, then it was going down to my wrist," she said, adding that humidity made the ball feel heavier.
"I don't know what happened there. But it is a new injury," she said.
"Hopefully I will recover for the tournament in Beijing, which is really important for me. But we will see," she said.