Sergio Aguero will miss Manchester City's Champions League game with Porto on Wednesday - but boss Pep Guardiola says the problem is not serious.
Aguero was absent for Saturday's 5-0 win over Burnley with a knee problem and has not returned to training.
The 32-year-old Argentina striker has only played four times this season.
"I am not concerned. He did not train. He had a little disturbance in his knee. It is nothing serious," said Guardiola.
City have already booked their place in the last 16 after winning their first four games. A draw in Portugal will seal top spot.
"We go there to get first place in the group stage. The important thing is done - to qualify - but we go to maintain our rhythm," Guardiola said.
"The Premier League is the main priority in general terms. We have 19 players in the first team fit and all of them travel. They are a really difficult opponent and we need the best players possible.
"Some players are going to play who didn't play the previous game.
"There are a lot of games but I don't want them to feel this is rotation. Every game is played with the best players for the circumstances for a specific game."
Entertainment data company Nielsen's Gracenote say Manchester City have 99.9% chance of progressing to the knockout stages.
Simon Gleave, head of sports analysis at Nielsen's Gracenote said: "As one of only four teams to have taken maximum points from the first three matches, it is no surprise to find Manchester City are near certainties for a place in the knockout stages.
"The Euro Club Index
estimates City have a 97% chance of winning Group B and a 99.9% probability of finishing in the top two."