Manchester City manager Manuel Pellegrini insists his side is not "Aguero dependent".
The Argentinean was injured early in the game against Everton on Saturday afternoon and will almost certainly miss the mid-week game against Roma in the Champions League, as confirmed by the Chilean.
"It is not good news, I don't think he will be able to play [against Roma]," Pellegrini said on Sergio Aguero's injury.
"We must wait for the diagnostic, the important thing he will not play against Roma and that is a very important game. It's impossible to know how long he will be out.
"He has a problem with his ligament in his knee and on Sunday we will know better how serious it is.
"It's very difficult if you have trouble in your ligament to recover in a few days. Of course it's a big problem, because Sergio was in a very good moment and is an important player for our team.
"Of course I always say this team is not just Sergio Aguero.
"The way we won was important for what we showed in defence. Sometimes it's important to just win 1-0.
"We had a chance to score another goal and didn't so I am pleased for the defence because they are criticised a lot, but I thought they did very well.
"It was important for a lot of things. Chelsea lost their game and it was important to recover the points and to be the near the leaders.
"December is a very different month where we have to play a lot of games.
"It's a month where maybe you don't win the title as such, but it is a key month to try to start the next year near the top."
