The Iceland international suffered a hip injury during the latter stages of Saturday's 2-1 defeat at Scunthorpe but hobbled on as three substitutes had already been used.
On-loan Burnley full-back Richard Eckersley - recalled at left-back in place of Chris Barker - is also an injury doubt after suffering an ankle injury.
Eckersley was replaced by substitute Barker after 23 minutes at Glanford Park.
With Arnason and Eckersley struggling, Barker - who can play at centre-back or left-back - comes into consideration along with new on-loan West Ham central defender Bondz N'Gala, who was an unused substitute at the weekend.
Winger Craig Noone (knee) is ruled out.