Sergio Aguero has sustained a groin injury in training with Argentina and is now doubtful for the 2014 World Cup qualifier against Bolivia.
Aguero suffered a similar injury while representing Manchester City during the 4-0 victory over Blackburn at the start of October, and Argentina boss Alejandro Sabella has said the forward may miss Friday's game against Bolivia.
Javier Pastore, of Paris St Germain, is in line to replace him if he fails to prove his fitness.
"Sergio Aguero has a sore groin and is doubtful for the match against Bolivia," Sabella told the Argentinian Football Association's official website. "In the event that Aguero does not play, Javier Pastore may replace him.
"The rest of the team to play Bolivia is: Sergio Romero, Pablo Zabaleta, Nicolas Burdisso, Martin Demichelis, Clemente Rodriguez, Fernando Gago, Javier Mascherano, Ricardo Alvarez, Lionel Messi and Gonzalo Higuain. We do not know whether Aguero will be able to play."
Argentina's next qualifier is against Colombia on Tuesday.