"I can't understand why I was sent off," he said. "I approached the referee after the game and he said it was for an obscenity."
Anderlecht coach Frank Vercauteren said he would not take any action until he checks the referee's report.
"If it was racial abuse, I cannot condone that," he said. "The other player should also have been sent off as well. He said something similar.
"These things should not be said, but I do not intend to punish my player further."
UEFA's investigation could take up to 15 days to reach a conclusion.