Roberts has a hip problem while forward Hunt picked up an unspecified knock in Saturday's FA Cup win over Sheffield United. McDermott is unlikely to play new signing Daniel Carrico as he comes to terms with life in England.
Petr Cech has failed to recover from injury for Chelsea's Premier League game at the Madejski Stadium. Cech has failed to shake off the calf strain that ruled him out of Sunday's FA Cup fourth-round draw at Brentford, with Ross Turnbull once again earmarked to deputise.
David Luiz (calf) is still several days away from a return, while Eden Hazard serves the second instalment of his minimum three-match ban.