Chelsea are investigating allegations of racism made against two ex-coaches by three former youth team players.
The BBC has approached Williams for comment, while Rix declined to comment when approached.
In a statement Chelsea said they are taking the allegations “extremely seriously”.
It added: “We are absolutely determined to do the right thing, to fully support those affected, assist the authorities and support their investigations.”
The statement was read out by Chelsea’s director of communications Steve Atkins in Blues manager Antonio Conte’s news conference previewing Saturday’s match at home to Leicester.