Wlodarczyk, 33, the hammer world record holder has dominated her event, winning gold at the last two Olympics and four world titles.
After a knee operation she posted an Instagram picture of herself in a hospital bed with a brace on her left leg pointing to her other leg which had "Tokyo 2020" written on it.
"The goal is one," she wrote in the caption. "#Tokyo2020."
"Keep your fingers crossed," she added.
Her coach Krzysztof Kaliszewski told Poland's TVN24 commercial news channel that "During surgery, it turned out that... matters are a little more serious."
"I won't go into detail, but physiotherapy will last about three months," Kaliszewski added. "We won't rush anything. The goal is the Tokyo Games and a third gold medal."
"I'll do everything to prepare Anita properly," he added.
The IAAF World Championships are scheduled for September 27 to October 6 in Doha, Qatar.