Left-back Robertson is a major doubt for the game after suffering a knee injury during the 3-0 home defeat to Walsall on Saturday.
If Robertson fails to make the trip to Boundary Park, it could open the door for Kelvin Mellor to return to the team. Mellor started the season as first-choice right-back with the versatile Matt Tootle switching across to left-back.
Alex boss Steve Davis told the club's official website: "Gregor has a sore knee. I think it is a touch of tendinitis and he is struggling to be fit for Saturday."