Manchester City striker Sergio Aguero is set to return to action after this month's international break, manager Pep Guardiola has said.
City's record goalscorer could even have a chance of facing champions Liverpool in the Premier League this weekend but, with Guardiola saying no risks will be taken, that seems unlikely.
Aguero, who missed the start of the campaign after undergoing knee surgery in June, suffered a hamstring injury just three matches into his comeback against West Ham on October 24.
Guardiola said: "He's getting better but right now I don't know. We don't want (him) to make a step back again.
"I don't know about Liverpool but after the international break, for sure, he'll be ready."
With Gabriel Jesus already sidelined, Aguero's injury has left City without a recognised centre forward.
Ferran Torres, the winger signed from Valencia in the summer, has filled the position in the last two games against Porto and Sheffield United and could do so again as Olympiacos visit in the Champions League on Tuesday.
That would be if the game comes too soon for Jesus. The Brazil striker, who has been out with a thigh injury since the opening match of the season, is now back in training and nearing a return. He could be in contention to face the Greeks in the Group C clash at the Etihad Stadium or, if not, Liverpool on Sunday.
Guardiola said: "It's too early to know. He is doing better. He did one training session with the team. We'll see, but he's happy he's back.
"We are awaiting Sergio but we've been happy with Ferran, so we have an alternative."
Another attacking option would be to use Raheem Sterling in the centre as a false nine, but Guardiola hinted he would rather deploy him elsewhere against Olympiacos.
The City boss said: "He can play there when the opponents are defending a lot of spaces in behind. When teams come to press he can do it.
"When teams settle in the box for 90 minutes he's better down the sides than in the middle."
Guardiola insists the looming encounter with Liverpool will not affect his thinking for Olympiacos.
"Absolutely not," said Guardiola, whose side have started strongly in the European competition with back-to-back wins over Porto and Marseille. "It's the Champions League and you cannot make a false step, because after that we would struggle.
"We know that in the Champions League to qualify you have to secure your games at home and win at least one away.
"We did it in Marseille but now have to be sure that we can keep the points at home, so that is why now we have an incredible opportunity to make a huge step to qualify for the next round."
City already have a three-point advantage at the top of the group and another win could see them take a firm grip of the pool. That could open up the possibility of rotating the squad later in the group stage – a potential luxury amid an intense schedule – but that is not in Guardiola's thinking.
He said: "We want to qualify. This is the first step, even finishing second is good. Qualifying is the most important thing. In first (place) would be better and as soon as possible, but if it has to be the last game against Marseille at home it will be OK."
