Argentina have named Liverpool midfielder Javier Mascherano in their 2008 Olympic Games squad.
Mascherano, 24, became a crucial player for the Reds as they reached the UEFA Champions League semi-finals last season.
And manager Rafa Benitez previously admitted concerns about losing Mascherano as the future of Xabi Alonso remains unclear and it is not certain that Liverpool will secure the signature of Aston Villa captain Gareth Barry.
Mascherano, who has been included in Argentina's Under 23 squad as an over-age player, will now be missing for up to a month from late July.
It means Mascherano will be absent for both legs of the Champions League third round qualifier on 12th and 27th August.
Liverpool youngster Emiliano Insua, who signed a new long-term contract with the Reds on Wednesday, will remain on Argentina's standby list.
Other high-profile players such as Lionel Messi, Sergio Aguero and Juan Roman Riquelme will also be part of the squad travelling to Tokyo to play a friendly against Japan on 29th July before going on to Beijing.