Motherwell boss Stephen Robinson has concerns over five players as a bug has swept through Fir Park ahead of the Ladbrokes Premiership clash with Hearts on Saturday.
Defender Peter Hartley missed the midweek win at St Mirren with an illness and others are facing a race to be fit for the visit of the Jambos.
Hearts are without Steven Naismith after the forward suffered another hamstring injury.
Defenders Aaron Hickey and Aidy White are doubts while midfielder Oli Bozanic will be assessed after missing the midweek draw with Livingston through illness.
Motherwell provisional squad: Gillespie, Tait, Carroll, Grimshaw, Mugabi, Hartley, Gallagher, Donnelly, O'Hara, Maguire, Polworth, Campbell, Seedorf, Hylton, Long, Cole, Scott, Carson.
Hearts provisional squad: Pereira, Smith, Hickey, Berra, Brandon, Dikamona, Irving, Whelan, Bozanic, Clare, MacLean, Ikpeazu, Keena, Meshino, Mulraney, Wighton, Walker, Damour, Zlamal.