Dunne has not played all season due to a groin injury which has required three rounds of surgery, but he has joined up with the Ireland squad ahead of their friendly against England at Wembley on Wednesday.
The 33-year-old Aston Villa defender will not figure against England despite training under the watchful eye of physio Ciaran Murray at Watford's London Colney headquarters on Sunday evening as his team-mates went through their paces.
However, he could play some part against Georgia in Dublin next Sunday and there is an outside chance he could line up against the Faroe Islands at the Aviva Stadium five days later.
Trapattoni said: "Now is England and Georgia; the Faroes is a qualifier.
"He would have to be 100 per cent fit. Don't forget, this injury has been 10 months, one year. It was a bad injury and then he had surgery.
"Only if he was very, very okay, 100 per cent. But there are two or three questions: he is without a club; he is many months without a game; and it's a qualifier.
"But for us, he will be again important in the future," added the Italian coach. "I spoke with him and I clarified his position, his position with the club and his position for us. We need Richard in the future.
"But he has no club at this moment. I said, 'Richard, we will help you because you deserve respect, but you have no team at this moment and you must be careful because an injury could be for you very, very dangerous'.
"We have more respect for him. I said we will go step by step. We have these two opportunities and we can assess his condition after the next two or three days.
"Sure, I want to help him. He will not start the game, but during the game depending on the score, we could give him an opportunity to play with us."