Striker Sergio Aguero is set to miss Argentina's World Cup qualifier against Bolivia and Columbia after injuring his groin during training.
The 23-year-old has been in startling form since his move to Manchester City with ten goals in 14 games for the Barclays Premier League leaders.
However, a groin injury picked up during the win over Blackburn Rovers saw him miss his country's last qualifier against Venezuela, and a recurrence could see him miss important upcoming games for his club.
Upon the return from the international break, Roberto Mancini's side face unbeaten Newcastle United, before a vital trip to Napoli in the Champions League.
Visits to Liverpool and then Arsenal in the Carling Cup are preceded by the hosting of Norwich City and Bayern Munich before back-to-back games with Chelsea and Arsenal.
"Sergio Aguero has a sore groin and is doubtful for the match against Bolivia," said manager Alejandro Sabella. "In the event that Aguero does not play, Javier Pastore may replace him.
"We do not know whether Aguero will be able to play."
Argentina are second in World Cup qualifiing with one win and one defeat from their opening two games, loosing on their last outing in Aguero's absence against Venezuela.