The Serbian, who has five goals in eight matches this season, picked up a hamstring problem during a training session last week, and missed his team's 3-1 win over OFI Crete in the Greek Super League on Saturday.
The Premier League is stacked to the brim with talent.
Although Foden played in City's final game of last season, it was only to ensure he won a title medal, but this season he clearly has every intention of becoming a permanent fixture. As a defender, I think, 'can I get at him?
The Blues are treating their star man carefully after he was in action until the final weekend of the World Cup with Belgium, who beat England to finish third in Russian Federation.More news: Klopp: Beating Paris Saint Germain proved Liverpool can reach next level
Despite the pressing schedule, and the apparent need to secure those two players' futures, Sarri said he would not be calling Courtois and Hazard.
Jamie Carragher has called Eden Hazard the "best player in the Premier League". He then returned and has been on top form for the side, now leading the race for the Golden Boot with five goals in five games. "I hope he can recover in the next two or three days and maybe there is an opportunity that I can give him a chance", Sarri explained. We will try to do the same as the last game.
"I know that here in London there are lots of derbies but we have our first against Chelsea, at the top of the table so that is one motivation more to beat them".
West Ham manager Manuel Pellegrini is confident that Marko Arnautovic will be in the starting line-up for the London derby with Chelsea on Sunday.
City cut Chelsea apart to become the first Premier League champions to win the trophy since Manchester United in 2013.