The 20-year-old defender has put pen to paper on a contract with City after training with the Raymond McEnhill Stadium club during pre-season.
Richards is a product of the youth academy at the Championship outfit but was shown the door during the last campaign having not made an impact at first-team level.
Meanwhile, the Blue Square Premier newcomers have strengthened further by signing up their former youth team product Nick Eastham to their first-team squad.
Source: http://www.confguide.com/newsArticle.do?id=6947