Richards, who can also play on the wing, came through the ranks at his home-town club Derby County and signed a one-year professional deal before he was released in January 2013
He then joined Ilkeston FC before signing for Chester FC in December 2014.
Richards made sixty-nine appearances for the Blues – thirty-nine of which came in the National League during the 2016/17 campaign where he scored 8 times.
He signed for Dover in May 2017 and has made fourteen appearances and scored one goal.
Richards will join up with the rest of the squad as the Bucks travel to Southport tonight.