Sergio Aguero is a doubt for Manchester City's Premier League clash against Liverpool on November 8 due to a thigh injury.
Pep Guardiola revealed on Monday evening that he expects Aguero, who was substituted at half-time during Saturday's 1-1 draw at West Ham, to be out for a minimum of two weeks, with City set to take on champions Liverpool at the Etihad in 13 days' time, live on Sky Sports.
Speaking ahead of Tuesday's Champions League game against Marseille, Guardiola confirmed: "It will be two or three weeks, Sergio (Aguero) and (Benjamin) Mendy as well.
"Sergio was injured in the last game, muscular. When you are out for four or five months with a knee problem you always have a risk when you come back.
"We tried to handle it as much as possible, just 50-55 minutes every game. But it was not possible. It depends on the injury. We expect 10-15 days for sure minimum, or it could be three weeks or a month."
Aguero joins Gabriel Jesus, Fernandinho, Benjamin Mendy, Nathan Ake and Fernandinho on the sidelines.
The positive news for City is that defender Aymeric Laporte was fit enough to travel to France after a knock.
Guardiola added: "Kevin (De Bruyne) is back again and played a few minutes against West Ham. Aymeric is back too, Nathan is so close. Gabriel is close - one week to 10 days to come back. The rest will be two or three weeks."
'We could not afford Aguero or Jesus replacement'
With Aguero and Jesus out, City are without an experienced specialist centre-forward.
Asked if he wished the club had strengthened in that position in the summer transfer window, Guardiola said: "Maybe. We considered it and thought about it, and another type of striker, but we could not.
"It's not a club that wants revenues at the end of the year, it's what they want and what's best for the team.
"You know when you decide to buy a striker they have to be at the level of Aguero and Jesus and we could not afford it. This is the reality.
"I'm not saying the club didn't want to do it, not just in terms of strikers but in every position, but they wanted to make as strong a team as possible to make more games and better. But we thought 'OK, Sergio is back and we didn't expect Gabriel to be injured'. Sometimes it happens."