Dean Leacock is expected to make a return from injury later this month.
The Derby defender sustained a hamstring strain during the home victory against Crystal Palace towards the end of September that was expected to rule him out of action for several weeks.
However, the 26-year-old has made a swift recovery and is eyeing the game against Preston at Pride Park on October 16th as a possible comeback.
Rams boss Nigel Clough believes the centre-half may come into the reckoning for the trip to Millwall a week later if he can prove his fitness in a reserve-team game.
He told the club's official website: "Preston looks a little bit too early for Dean because of the nature of his injury.
"We hope he can feature in the reserve game against Rotherham just after Preston and then be available for selection after that."