The Greek champions were forced to sit out a second round of fixtures this weekend in a campaign being delayed because only 14 of the 16 teams have been confirmed to play in the top flight due to legal disputes after a match-fixing scandal.
"Our official matches start with the [Group F] game against Marseille in the first match of the Champions League and this is difficult for us," manager Ernesto Valverde said on the club website.
Their cause has also not been helped by the unexpected departure of Spanish winger Albert Riera to Galatasaray earlier this month.
"It is a great concern [that Olympiakos have not played a competitive match yet], as well as the departure of Riera," said Valverde.
"He was a key member of the team and there is a huge void to fill but we cannot cry about it. I prefer to work with players who want to be at this football club."
The Reds struggled to a goalless home draw in a friendly against OFI Crete on Friday.
Asteras Tripolis played their first match of the new campaign on Sunday, a goalless draw with Kerykyra, six days after they were reinstated into the top flight after Iraklis lost their appeal against demotion for forging a tax document.
Olympiakos Volos and Kavala have been demoted by the Professional Sports Committee (EEA) after failing to break ties with owners who have been implicated in match-fixing.
The same panel has not yet approved the licences of Doxa Dramas and Levadiakos, who are due to take the places of the two demoted teams.
The EEA's examination of the applications of the two second division clubs is expected to conclude next week.
Also on Sunday, Panathinaikos continued their 100 percent start to the season with a 3-1 home win over PAS Giannena at the Olympic Stadium.
Goals from Spaniards Josu Sarriegi and Toche put the Greens 2-0 up before striker Ibrahima Bakayoko's 65th-minute effort gave Giannena hope.
Panathinaikos' Argentine winger Sebastian Leto struck with 15 minutes left, however, to calm the hosts' nerves and seal the three points for Jesualdo Ferreira's men, who top the fledgling Super League table after two matches.
Elsewhere, Panionios were 1-0 winners at Panaitolikos, PAOK Salonica suffered a surprise 2-1 defeat by Ergotelis in Crete and Aris Salonica slumped to a 1-0 home loss against Atromitos.
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