Orr has not featured for the Robins since their 3-2 win at Barnsley on October 24 because of an Achilles injury, but he will be in the squad to take on Roy Keane's men. Cole Skuse is expected to continue in the right-back position, though.
Jamie McAllister has shown no ill-effects of the shin injury that has blighted him for the past fortnight and he is expected to play.
City go into the game looking to immediately get over last weekend's dramatic defeat to Sheffield United. The Blades led 2-0 at one stage, before City pulled level to 2-2 in the last minute.
But Darius Henderson then completed his hat-trick for United, ending City's 19-game unbeaten home run in the process.
