Motherwell defender Charles Dunne has suffered a setback in his bid to return from a long-term groin injury.
The centre-back has been troubled by a knee issue and has sought specialist help to overcome the problem.
Liam Donnelly missed Wednesday's Ladbrokes Premiership visit of Ross County through suspension but Christopher Long is back from a ban. Jake Carroll (Achilles) and Jamie Semple (knee) are out.
Ross County have striker Ross Stewart back in their squad for the first time in 2020 following a hamstring injury.
Coll Donaldson remains out with facial fractures but the defender could return sooner than expected.
Joe Chalmers (ankle) is nearing a comeback but Michael Gardyne (hamstring) and Tom Grivosti (foot) remain out.
Motherwell provisional squad: Gillespie, Tait, Grimshaw, Hartley, Gallagher, Mugabi, Campbell, O'Hara, Polworth, Turnbull, Hylton, Long, Watt, Aarons, Seedorf, Ilic, Manzinga, MacIver, Maguire, Carson.
Ross County provisional squad: Baxter, Foster, Fraser, Fontaine, Kelly, Watson, Cowie, Spittal, Paton, Mullin, Tillson, McKay, Erwin, Vigurs, Spence, Stewart, Shaw, Laidlaw.
