Barcelona says defender Javier Mascherano will be sidelined with injury for up to two weeks and is likely to miss next week's Champions League match against Celtic.
The club says its first-choice center back ''underwent medical tests on Wednesday morning'' which confirmed he has injured his right hamstring.
The injury was caused in the second minute of Tuesday's 4-1 league win over Real Sociedad in the Camp Nou when teammate Sergio Busquets accidentally struck Mascherano just above the knee with an outstretched boot.
Barcelona coach Gerardo Martino is currently without captain Carles Puyol, who has yet to return following knee surgery, and left back Jordi Alba.
Barcelona faces Group H rival Celtic on Tuesday and has upcoming league matches against Almeria and Real Valladolid.