David Silva and Fernandinho are injury concerns for Manchester City ahead of Sunday’s trip to Sunderland.
The Spanish winger was substituted in City’s 5-2 Champions League win over CSKA Moscow on Tuesday night, when he was replaced by Aleksandar Kolarov.
And he has been forced to cancel a planned trip to London to report to City’s Carrington training ground on Wednesday for treatment.
Earlier, Brazil midfielder Fernandinho had been substituted at half-time, with James Milner replacing him after the break.
And manager Manuel Pellegrini said after the game: "David Silva and Fernandinho both had to be substituted. They have small problems, so we'll see with the doctor."
Fernandinho has only missed one league game so far this season while Silva, who injured a thigh on international duty with Spain in September, has been an automatic choice when fit.
Striker Alvaro Negredo scored his first City hat trick in the win against CSKA to take his tally to five goals in his last three games.
And the former Sevilla forward told the club’s official website: "I could not ask for more. I am very happy with everything, for the hat trick and the goals I am scoring. The most important thing was the victory and we've got it."
The win secured City’s place in the last 16 of the competition and Negredo added: "That was the most important thing. That was the goal and we've achieved it with two games to spare. That's what we all wanted."