The former Toon striker only signed a three-year contract on May 25.
It doesn't take long for the pressure to mount in the Greek league, he's only been in charge for two games - a 2-0 away victory over Larissa and a goalless home draw with Kavala.
Olympiakos host Dutch side AZ Alkmaar at the Georgios Karaiskakis stadium on Wednesday in their first Group H match.