Barcelona could be without Sergi Roberto for the next few weeks after he was forced off with a hamstring strain against Olympiakos on Tuesday.
Roberto, 25, picked up the injury at the end of the first half of his side's Champions League game at the Karaiskaki Stadium in Athens.
The midfielder stayed down after earning a booking for a foul on Vadis Odjidja-Ofoe and had to be replaced by Gerard Deulofeu.
"Sergi Roberto has a right hamstring strain," the Catalan club confirmed in a brief statement. "On Wednesday he will have more tests to find out the exact extent of the injury."
Roberto has been one of Barcelona's most in-form players in recent weeks playing as a right-back, but he returned to midfield against Olympiakos as he made his 10th start of the campaign.
Injuries have been fairly kind to Ernesto Valverde's Barca so far this season but there has been a spout of problems recently.
Javier Mascherano and Jordi Alba both played in Greece after recovering from a foot infection and a thigh strain respectively, but the Blaugrana were without a number of other players.
Captain Andres Iniesta is sidelined with a thigh problem, while Ousmane Dembele, Rafinha, Arda Turan and Aleix Vidal also have fitness problems.
Luis Suarez, meanwhile, has been playing with a knee injury and will miss two Uruguay games during next week's international break in a bid to heal the problem.