Birmingham defender Stephen Carr has been given a one-game ban after accepting a Football Association charge of improper conduct following an incident during Sunday's fiery derby defeat at Aston Villa.
Carr is alleged to have made an offensive gesture to Villa fans at the end of the match which Villa won 1-0 thanks to a late, controversial James Milner penalty.
West Midlands Police are also expected to question Carr over the incident.
Carr, who requested a personal hearing to explain his version of events, will sit out Saturday's Premier League game against Burnley at St Andrew's.
Birmingham were also charged on Tuesday with failing to control their players after referee Martin Atkinson awarded the spot-kick when defender Roger Johnson was adjudged to have fouled Villa's Gabriel Agbonlahor.
Birmingham have until May 13 to respond.
Johnson has been asked by the FA to explain his claim afterwards that Atkinson was "a disgrace".
TV replays showed the defender had got a touch on the ball and Johnson said: "The referee was a disgrace. He's ruined the match and clearly shouldn't be doing these kind of games - it was too big for him."