However, after working with the striker this week, Worthington has seen a significant change in the country's record scorer, who has failed to find in the net in seven qualifiers.
Related ArticlesSlovenia 0 Northern Ireland 1Johnny Gorman gets Euro 2012 chanceMontenegro 2 N Ireland 0Albania 1 N. Ireland 0Evans withdraws from Northern Ireland squadWorthington to stay as NI managerHe is convinced Healy, who scored the winner against England and a hat-trick in the victory over Spain in recent years, is ready to test the world's best again.
Worthington said: "David has had a lean time, like all strikers do, but I am working with him and he can still finish. It is really about confidence and self-belief.
"I have seen a difference in David this week and in the past month compared to the last two years.
"He is sharp and bright and around goal he looks as though he is ready to sniff something out like he did in the past. So he has got my full backing."
Northern Ireland go into the match on a high after beating Slovenia in their opening qualifier, thanks to a goal from Manchester United rookie Corry Evans.
Cheering them on will be five of the remaining seven survivors of the 1958 World Cup side.
Harry Gregg (Manchester United), Norman Uprichard (Portsmouth), Peter McParland (Aston Villa), Jimmy McIlroy (Burnley) and Billy Bingham (Sunderland) have all been invited by the Irish Football Association.