Burnley are waiting to learn the extent of the illness which forced Jack Cork out of the England Under 21 defeat by Iceland.
Cork was replaced during Monday's 2-1 loss at Deepdale after suffering palpitations and was taken to hospital.
Medical tests are being carried out on the on-loan Chelsea midfielder and it is suspected that Cork is suffering from a virus.
England Under 21 coach Stuart Pearce said: "He had palpitations in the first half and said he wasn't feeling so well so we have taken him to hospital just for precautionary status.
"That's as far as I know at the moment but obviously our doctors will be in contact with the hospital."
Cork has scored three goals in 33 Championship appearances for Burnley this season and has previously suggested he would be keen on a permanent move to Turf Moor.