The 56-year-old returns to African football following previous successful spells with Orlando Pirates, Raja Casablanca and JS Kabylie.
Zinnbauer most recently managed Algerian side JS Kabylie until March 2026. Prior to that, he guided Raja Casablanca to an unbeaten league title and domestic double in Morocco, and earlier enjoyed a productive period at Orlando Pirates in South Africa.
An official announcement from Al Hilal is expected in the coming days as the experienced tactician prepares for his new challenge in Sudan.