Not all great players become good managers, even when they try.
From the Greeks:
Sideris became a gold merchant
Nestoridis-Papaioannou-Mavros-Nikolaidis: No
Anastopoulos: Yes, of smaller clubs
Negreponte-Maropoulos, the pre-war legends: Yes
Domazos: In his days as a player wanted to give orders to everybody but never became a manager.