The winger picked up the problem at the end of the first half was he was hacked down by Raul Navas who received a yellow card, and should probably have been sent off.
Dembele did continue for a bit but was then taken off in the second half and the club have now confirmed the nature of the injury.
“The first team player Ousmane Dembélé has a sprained right annkle. In the next few days he will continue under the supervision of the Club’s medical staff,”
Source | Barcelona
The Frenchman will surely be relieved to have escaped serious injury, particularly with the World Cup just around the corner now.