Hearts midfielder Laryea Kingston has aplogised for accusing referee Steve Conroy of being a racist.
The Ghanian international was sent off against Aberdeen and has expressed his "sincere regrets" at his comments.
BBC Scotland reported that several players heard the accusation made by Kingston during the 1-0 defeat.
Kingston had been booked early in the second half for persistent fouling and shown a second yellow card after a clumsy challenge on Barry Nicholson.
Now he faces Scottish FA action after reacting badly to being sent off.
Kingston spoke to Hearts News about his feelings.
He said: "I am extremely sorry for the events on Saturday afternoon.
"While I am still disappointed at the decision for the second yellow card, I must express sincere regret at the comment I made of the referee.
Kingston continued: "It was completely out of character and is in no way part of my make-up.
"I will, at the earliest opportunity, apologise to Mr Conroy as I feel I over reacted and I would hope that my record since coming to Scotland and my future conduct will demonstrate that I am only interested in playing top class but fair football."
Meanwhile, Hearts assistant coach Stephen Frail refused to concede that his side's bid to qualify for the Uefa Cup is now over despite Aberdeen moving three points clear in third spot in the Scottish Premier League.
"We are not out of it yet," said the number two to interim head coach Anatoly Korobochka.
"It makes things more difficult, but Aberdeen didn't secure European football today and we just need to learn from what happened, get back on the training ground and build towards facing Dundee United at the weekend.
"However, to be honest, I don't think we deserved to take anything from this game as Aberdeen were hungrier, showed more desire and created more chances.
"We now need to try to get some players back such as Roman Bednar, Saul Mikoliunas, Robbie Neilson and Neil McCann.
"Hopefully, we can get them fit and keep fighting for a place in Europe."