Greece have named Kostas Tsanas and Nektarios Pantazis as interim coaches of the national team, but has yet to officially confirm Claudio Ranieri's sacking.
The 63-year-old Italian took over the Euro 2004 champions in July, but is expected to be dismissed after Friday's shock 1-0 home defeat by the Faroe Islands.
A statement from the Greek Football Association read: "The Hellenic Football Federation announces that the role of interim coach for the friendly match with Serbia will be [carried out by] Kostas Tsanas and Nektarios Pantazis."
The delay in announcing Ranieri's departure is said to be because of discussions over a compensation package.