Álvarez suffered the injury late in the game in a collision with Everaldo Stum.
Club doctor Francisco José Marbán reported that the goalkeeper suffered multiple fractures to the left side of his face, including the zygomatic bone and the eye socket. The eye itself was not injured.
Álvarez will undergo surgery on Wednesday or Thursday to repair the fractures, and a timetable will be set for his return after the surgery.
The goalkeeper will wear a protective mask when he returns to the field.