Midfielder Danny Rose and strikers David Clarkson and Brett Pitman are pushing for recalls after making an impact from the bench in the 1-1 draw with Crystal Palace on Tuesday.
Millen still has defensive problems. Liam Fontaine (ankle) and Jamie McAllister (calf) could be out for some time, while Louis Carey and Christian Ribeiro are not expected to be fit to face the Bluebirds or Championship leaders QPR on January 3.
Of the walking wounded, the closest to making a return is captain Carey who is recovering from illness and a torn calf muscle.
"Louis is back training now but is working on his own with the physios. This weekend is probably too soon for him but at least he is on the mend," said Millen.
Last season's top scorer Nicky Maynard has been back in training for a month and is close to making a comeback, but Millen added: "We are not setting any target dates for him. We have to be careful with Nicky and we will look at his situation week by week."
Source: PA
Source: PA