Coventry City club captain Sammy Clingan has returned to the club from international duty to be treated for his back injury sustained in the 2-1 home defeat in the Euro 2012 qualifying game against Estonia.
The injury means Clingan will miss Northern Ireland's trip to Italy as he struggles to recover in time for Saturday's home game against one of his former clubs, Nottingham Forest.
The influential midfielder suffered a back spasm half an hour into the Estonia game and had to be replaced, but the cause and extent of the injury is currently unknown, but Thorn is hoping that, with treatment, Clingan will be fit to face Forest on Saturday.
Thorn told the CT: “I spoke to Sammy at the weekend and he said he was really sore so he came back and has been getting treatment here.
“Hopefully he will respond to that and be fit for the weekend but we’ve got to get to the root of the problem first.”