Raphinha was substituted by coach Carlo Ancelotti complaining of "muscle discomfort" in his right leg.
Barca are now waiting for contact with Brazil'a medical staff to learn the exact extent of the injury, once he undergoes scans in the morning.
A decision will be made whether Raphinha is to remain with his national team, as Brazil faces Croatia in another friendly on Wednesday, or if he will return early.
Inside Barcelona's offices, they're keeping their fingers crossed and, despite the concern, are hopeful that it's just discomfort and that Raphinha hasn't suffered any serious injury.
However, according to some reports coming from the Brazil camp, the player could have a hamstring tear, the same area that sidelined him for two months at the end of last year.
If confirmed, it would be a serious setback for the Catalan side at a crucial point in the season.