Bacary Sagna has been asked to explain himself by the Football Association following a social media post which may have questioned referee Lee Mason's integrity.
The Manchester City full-back wrote "10 against 12.. but still fighting and winning as a team" on Instagram after Monday's hard-fought 2-1 victory over Burnley at the Etihad Stadium. The post was later amended to read "still fighting and winning as a team".
Press Association Sport understands the FA has asked Sagna for his observations and he has until 5pm on Friday to respond. A decision on whether a charge follows will be made in due course.
City were annoyed by some of Mason's decisions during the game. The first major talking point was the sending off of Fernandinho after 32 minutes while City also felt Burnley's goal should have been disallowed for a foul on Claudio Bravo.
The FA has rules in place concerning social media and participants are not permitted to question the integrity of officials.