Barcelona says defender Javier Mascherano will be sidelined for about a month because of a hamstring injury.
Mascherano hurt his right leg while playing in Argentina's 4-2 loss to Nigeria in a friendly in Russia on Tuesday.
Tests conducted on Wednesday in Barcelona showed the extent of the injury.
The 33-year-old Argentine played the entire game against Nigeria.
Barcelona's next game is Saturday at Leganes in the Spanish league.
The Catalan club leads La Liga with 31 points from 11 matches, four points more than second-place Valencia.