Memphis Depay broke the biceps femoris in his left leg on Thursday, according to Javi Miguel.
The player will most likely be ruled out for up to one month with the injury.
The Dutchman will miss crunch La Liga games against Mallorca, Celta Vigo and El Clasico. In the Champions League, the striker is ruled out of the double-header against Inter Milan.
Barcelona were hit hard with injuries on the first matchday of the September international break with Jules Kounde, Memphis, Ousmane Dembele and Frenkie De Jong all facing one injury scare or the other.