The England international was not fit enough to even make the bench as the Blues hosted the Premier League champions at Stamford Bridge.
Chelsea boss Graham Potter confirmed the problem shortly before kick-off, telling Sky Sports: ‘He had a kick in training yesterday, so it never rains but it pours as they say.’
Potter gave no more details and The Athletic reports that the severity of the injury has not been confirmed, but the hope at Chelsea is that it is pretty minor.
It is a big loss for Potter as the 23-year-old has been a key figure so far this season, appearing in all 16 of Chelsea’s Premier League games, with 15 of those coming in the starting XI.
In Mount’s absence, Denis Zakaria and Mateo Kovacic start in central midfield for Chelsea against City, with Raheem Sterling, Hakim Ziyech and Christian Pulisic ahead of them behind Kai Havertz.
Mount joins five other Blues stars on the sidelines, with N’Golo Kante, Reece James, Edouard Mendy, Wesley Fofana and Armando Broja all out.
Fofana and Mendy are not too far away from a return, but James, Kante and Broja will not be back this month.
Potter told Sky Sports: ‘In the end you are trying to find a solution: How do you replace Reece James? How do you replace N’Golo Kante? How do you replace Wesley Fofana? These are guys that are key players for us. I don’t want to make excuses, it sounds like them. We need stability and we are working towards that.
‘We need to be consistent with the shape and try and be consistent with the players we have. We’ve lost James and Mason Mount since our last home game. That is just the life you have as a football manager. That affects consistency.
‘When you’re playing Saturday, Tuesday, Saturday, Tuesday, it would be nice to say we have 11 players and we’ll roll them out all the time, but that isn’t the reality that you have. You have to adjust, and of course if results don’t go well you get criticism for that. If you don’t change your formation and you lose you get criticism. It is what it is. You have to accept it.’
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