Sarr has been extremely versatile, occupying many positions in the defensive third, including playing on the left side of a back three.
The 1-0 defeat means Man City have now extended their lead over the Blues to 13 points in the Premier League with a 12th consecutive home win.
The Blues completed the formality in north London, bagging a 1-0 win to set up a final date with one of Liverpool or Arsenal.
Chelsea beat Tottenham Hotspur 3-0 on aggregate to go through to the Carabao Cup final.
The Blues lead the tie 2-0 after Kai Havertz’s early strike and an own goal by Ben Davies gave Chelsea FC the victory in the first match.
The duo tested positive last week and missed the 2-0 first-leg victory over Spurs as well as the FA Cup win over Chesterfield.
Chelsea thrashed Chesterfield 5-1 in the FA Cup fixture at Stamford Bridge on Saturday.
He recently passed 450 Blues appearances and started his 300th Premier League game in the draw with Brighton last week.
With more injuries and positive Covid tests in his squad, Tuchel had to make six changes to his team from the side which drew with Liverpool at the weekend.
He was playing on the right side of midfield in the first half and was pushed slightly further upfield in a front three after the break.