The 35 year-old veteran joined the Millers until the summer back in January, but has been sidelined with a knee problem for much of his spell.
Boss Patto told the Star: "Richard is still struggling. He tried to step up his rehabilitation last week but it is slow progress unfortunately. But he's a winner.and a fighter. It is more frustrating for him mentally because he wants to be out there playing.
“I expect him to comeback from this and continue his career."
Meanwhile Michael Raynes is set to miss Fridays trip to Wimbledon as he is struggling to shrug off an ankle injury that kept him out of last weekends win over Hereford United.