Police are investigating claims that Rotherham striker Jonson Clarke-Harris was racially abused by a Bradford fan after Saturday's League One match.
The 23-year-old says he was abused by a home supporter as he warmed down on the pitch after the Millers' 1-0 defeat.
Bradford have apologised for the alleged incident and say they have been given a first name for the person believed to have been involved.
Clarke-Harris had come on as a sub in the game at Valley Parade.
He posted on his Twitter account: "To that one Bradford fan doing monkey chants at me as I was doing my runs at the end off the game, you should be disappointed in yourself."
Bradford have passed information about the allegation onto the police, including CCTV footage.
The club said in a statement: "The club will work closely with Rotherham United and the West Yorkshire Police to continue our investigation into this incident, confirm the individual involved and take appropriate action."
Rotherham put out their own statement, saying: "Rotherham United operate a zero-tolerance policy on discrimination of any kind, and will fully assist with any ongoing investigation into the incident."