Robbie Brady could be facing a ban that would rule him out of next month's World Cup play-off.
FIFA is investigating accusations of a headbutt from the Republic of Ireland midfielder in Monday's game against Wales.
He's alleged to have put the head into the back of Welsh defender Ashley Williams, after an off-the-ball clash between the pair.
This is the incident in question:
If Brady is ruled out of the game, then it would be a huge blow for the Boys In Green, who are already without David Meyler through suspension after his injury time yellow card in the game in Cardiff.