Elano, 29, picked up the knock in a crunching tackle in the 3-1 group stage victory against the Ivory Coast. The former Manchester City star has been sidelined since, and the Selecao's team doctor has refused to set a return date.
Speaking to reporters, Jose Luiz Runco said: "He can walk and run without changing direction, the problem is the impact, when he puts weight on it.
"The bone is swollen inside, hence the name.
"He could be better in a few days, a week or a month. We still hope he can play next week but I can't say that categorically. He is working intensely so we have to see if nature can give a helping hand."
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