Lazio midfielder Senad Lulic has issued an apology for aiming a racial slur at Antonio Rudiger, but could still face a ban of up to 10 games.
Lulic said the Roma defender had been "selling socks and belts" a few years back and should not be "acting like God's gift" after Roma's win in the derby.
Lazio also issued an apology on behalf of the 30-year-old, who said he regretted words he had used in the heat of the moment.
"Now I have had time to consider things, I realise that I responded to a provocation with another provocation," Lulic wrote on Facebook.
"I come from a country [Bosnia] which knows all about tragedies caused by ethnic prejudices, and for this reason I am sorry that I let the post-derby tension get to me and expressed myself in an unfortunate manner."
The Lega Serie A disciplinary committee will now consider what punishment to impose.
A similar case two years ago saw Atalanta's Alberto Grassi banned for 10 games after he racially insulted an opponent in a youth game.
If the same sanction is applied to Lulic, he could be out of action until Lazio host Udinese at the end of February.