Brazil forward Alexandre Pato has suffered an injury scare just two weeks before the start of the Olympic Games.
The 22-year-old picked up an ankle knock in training on Friday in a challenge from teammate Juan.
The AC Milan attacker could now miss his country's Olympic opener against Egypt on Thursday, July 26.
Pato, who is expected to receive treatment on his ankle, missed much of last season for the Rosonneri with a recurring thigh injury.