Neto has been ruled out of Barcelona ties for up to eight weeks following his a fractured left wrist injury.
After experiencing the injury before the 4-0 weekend victory over Napoli in Michigan, the fresh signing underwent an operation on Tuesday.
The shot-stopper, Neto joined Barca from Valencia in June as Jasper Cillessen moved in the opposite direction.
Not making up the squad immediately will see 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.