Barcelona have confirmed Lamine Yamal is out of action with a hamstring strain after the forward returned early from Spain duty.
Yamal has undergone further tests at Barcelona and has now been sidelined temporarily.
Here's the club's statement:
"Tests carried out this morning on first team player Lamine Yamal have confirmed that he has a left hamstring strain. His return to training will be determined by his recovery time."
The news means that Yamal is now a doubt for Barca's next game against Sevilla in La Liga on Sunday.
Indeed Flick may not want to risk him in that game at all as Barca then play Bayern and Real Madrid.