Rotherham have been assessing Shaun MacDonald ahead of Wednesday’s Sky Bet Championship home clash with Luton.
The midfielder picked up an injury in the 1-0 loss at Stoke on Saturday, came off around the hour mark and then did not train on Monday.
Sidelined pair Chiedozie Ogbene (knee) and Clark Robertson (metatarsal) are both facing a number of months out of action.
Paul Warne’s Millers have recorded victory only once in eight games since winning their opening match of their league campaign.
It remains to be seen if there is involvement for Luton defender James Bree in the match at the New York Stadium.
Boss Nathan Jones said after Saturday’s 3-0 loss to Brentford that the right-back, who has not played since September 19 due to a knee injury, was back in training but “how quickly we can get him in is another thing”.
Jones also said Brad Potts was “a little way off”, while the fitness of Potts’ fellow left-back Rhys Norrington-Davies may also be a concern after his withdrawal at half-time at the weekend.
Harry Cornick was thought to be in contention for the Brentford game but did not feature in the matchday squad.