Oldham Athletic, the club where Richards began his career, are entitled to 20% of any transfer fee as part of a sell-on clause.
Following City's 2-1 win against Everton on Monday, manager Stuart Pearce also dismissed speculation over a Richards deal with Chelsea.
"There has been speculation that a deal has been done with another club,"
said Pearce. "That is a blatant lie.
"The one thing I can say is Micah is fantastically happy at this club. I want to bring players in to add to the quality players we already have.
"The main thing is he doesn't let his head get turned by what they read in the papers. Sometimes that is difficult for an 18-year-old."
Meanwhile, City goalkeeper Joe Hart has joined Tranmere Rovers on a month's loan.