Brazil and AC Milan playmaker Kaka may require an operation on his left knee, Globo television reported on Wednesday.
The World player of the Year will be examined on Friday by Brazil team doctor Jose Luis Runco in Rio de Janeiro to decide whether he will have to undergo surgery, Globo said.
The surgery would put Kaka out of action for about 15 days, ruling him out of the friendlies against Canada and Venezuela, the report said. He could also miss next month's World Cup qualifiers away to Paraguay and at home to Argentina.
On Sunday, AC Milan said they would not allow him to take part in the Olympic Games tournament as an overage player. The 26-year-old has been troubled this season by fitness problems.