The Frenchman was named in the starting XI but lasted only a few minutes before picking up a problem and being replaced by Alex Collado.
The 21-year-old then went and sat on the bench where he had an ice pack strapped to his thigh.
Barcelona subsequently confirmed he has suffered a hamstring injury and will undergo more tests on the problem:
❗ [BREAKING NEWS] O.Dembélé has a hamstring injury in his right leg. He'll undergo tests tomorrow to determine the exact extent of the injury. pic.twitter.com/q3Ze4JijJE— FC Barcelona (@FCBarcelona) May 4, 2019
It’s not clear how serious the injury is but it certainly looks unlikely he will be in the starting XI for Tuesday’s Champions League semi-final second leg against Liverpool.