Bishop Gerardi was killed in 1998 after he accused the Guatemalan army of serious violations of human rights.
Father Mario Orantes and three military men were convicted and sentenced last summer for the murder.
José Toledo, the attorney for Father Orantes, said the verdict might be appealed in January. All that was needed was the appeal of one of the three military men, in order to establish the date and time for a court hearing.
Father Orantes was sentenced to 20 years in prison for complicity in the murder. Also convicted in July and sentenced to long prison terms were Byron Lima Oliva, his son Byron Disrael Lima Estrada, and Obdulio Villanueva.
If authorities agree to a new trial, it would be heard in the Fourth Chamber of Guatemala´s Supreme Court of Justice.