Barcelona defender Javier Mascherano is set to miss four weeks of action with a hamstring injury sustained on international duty.
Mascherano picked up the problem during Tuesday's friendly between Argentina and Nigeria, which ended in a 4-2 victory for the African nation.
The 33-year-old underwent tests on his right leg on Wednesday morning and the results confirmed he will be sidelined for around a month.
That absence will likely see Mascherano miss matches against Leganes, Juventus, Valencia and Real Murcia, although he should be fit by the time El Clasico rolls around – Barca visit the Santiago Bernabeu on December 23.
Mascherano played the full 90 minutes of Argentina's clash with Nigeria and has made a total of 10 appearances across all competitions for Barca this season.
The Catalan giants hold a four-point lead over Valencia at the top of La Liga.