Sergino Dest could be out for the rest of the season after suffering a hamstring injury during Barcelona's defeat to Rayo Vallecano on Sunday.
The United States international was replaced by Clement Lenglet at half-time due to damage he sustained in the first half of a 1-0 loss at Camp Nou.
Dest underwent tests and Barca confirmed the full-back has injured his right hamstring but did not put a timescale on his absence.
A club statement said: "Tests carried out on Sergino Dest have confirmed that the player has injured the semitendinosus muscle in his right hamstring.
"The player is unavailable for selection and his recovery will dictate his return."
Barca's third consecutive home defeat left runaway leaders Real Madrid needing only a point from five games to win the LaLiga title.
The second-placed Blaugrana travel to Copa del Rey winners Real Betis for their next match on Saturday.