Aston Villa shot stopper Emi Martinez was replaced by Robin Olsen for their game against Manchester City.
The Midlands club were unable to keep pace with the reigning Premier League champions.
City ran away 4-1 winners on the night, with Phil Foden scoring a hat-trick.
There is no suggestion that Martinez has a long-term issue that caused him to miss the game.
He was declared ill on the day and the club felt that he was not well enough to play.
Martinez is hoping to push his team towards Champions League qualification.