According to today's Daily Express (a rag I know):
"Fulham winger Damien Duff's calf injury is not as bad as first feared. The 30-year-old limped out of Saturday's 1-0 home defeat by Arsenal after only nine minutes and will miss Thursday's Europa League match with Basel. However, he is expected to be fit for the visit of Roma on 22 October."
If Duffer's injury is not so severe then two weeks to the Montenegro game might give him a chance.