Barcelona defender Samuel Umtiti went off with what appeared to be a hamstring injury midway through the second half against Celta Vigo.
He pulled up after chasing a ball on the left of the defence in the build up to Celta's second goal and he had to be replaced by Thomas Vermaelen.
It means that he could be missing for key games later this month against Sporting in the Champions League, and Villarreal, Deportivo and in particular Real Madrid, in LaLiga.