Barcelona have ruled goalkeeper Neto out for up to eight weeks with a fractured left wrist.
The new signing underwent an operation on Tuesday after suffering the injury prior to the 4-0 weekend win over Napoli in Michigan.
Neto joined Barca from Valencia in June as Jasper Cillessen moved in the opposite direction.
His absence leaves the LaLiga champions without an experienced competitor for first-choice Marc-Andre ter Stegen ahead of Friday's season opener against Athletic Bilbao.
Inaki Pena, 20, is expected to be promoted from Barcelona B after travelling with Ernesto Valverde's squad to the United States.
The timescale placed on Neto's recovery could keep him out until after the international break in October.