Interim manager Paul Warne says striker Danny Ward will travel with the squad as he battles to overcome a calf injury ahead of the clash with Cardiff City.
Ward was withdrawn in the midweek defeat to Huddersfield Town with the complaint which has cast doubt over his involvement against Neil Warnock's Bluebirds.
Warne confirmed the top scorer will be assessed as late as possible ahead of Saturday's showdown, with the likes of Jerry Yates, Jon Taylor and Dexter Blackstock all waiting in the wings.
"He is struggling," Warne confirmed to www.themillers.co.uk
"Obviously he has hurt his calf. He had a bit of fatigue in it on Saturday and he cramped up with it a little which is normally a sign. I spoke to him today and he will be travelling with the squad tomorrow and then we'll reasses it."
There was better news on the injury front for Warne as he prepares to welcome back two key faces who have been missing in recent weeks.
Darnell Fisher and Aimen Belaid are both back in contention after being forced off in the recent home game with Barnsley.
"Both will be in the squad," Warne confirmed.
"They have both done full training all week. I have just spoken to Aimen, and I spoke to Darnell by text and they both feel good. They will be on the merry bus tomorrow for the journey to Wales. I will decide how much to play them, or if to play them, later on. They are both available."
The Millers will be without midfielder Tom Adeyemi and defender Semi Ajayi who are unable to play under the terms of their loan agreement from Cardiff.