Gibson decided to make himself unavailable for Ireland under Giovanni Trapattoni in reaction to the manager’s decision to give him no game-time at the Euros last summer.
While Trapattoni and his assistant Marco Tardelli have talked up the prospects of the player making a comeback, Gibson has yet to change his stance.
Duffy knows the quality which Gibson can supply to the Ireland and is anxious for his return. However, there’s still a degree of doubt about any potential comeback.
“He is probably one of our best players at the minute and hopefully we can get him back playing for Ireland,” said Duffy, who will lead Ireland’s U21s out against Holland tomorrow at Tallaght Stadium (1pm kick-off).
“I haven’t spoken to him about the Irish situation because it’s his matter. I don’t know what’s happening or why he hasn’t come back. I’m not sure.
“Perhaps it’s just injuries but I don’t know why he’s not in the Irish squad. He played a match on Saturday against Aston Villa and came off near the end.”
Duffy himself, meanwhile, is aiming to seal to secure a loan move from the Toffees by the end of the week.
With just two substitute outings to show so far this term, the 21-year-old wants first-team football elsewhere to boost his prospects of an Ireland senior squad recall.
“I had a chance to go to Middlesbrough at the start of the season but the manager needed me as cover because Tony Hibbert got injured,” he explained.
“The loan window reopens this Thursday and I’ll likely move to a Championship club then. I must have been on the Everton bench for 40 games this season!
“The Ireland manager telephoned me before the Greece game in November, saying I needed regular games to get into the squad. Hopefully as soon as I’m getting matches on loan, I’ll be in the senior squad.”
He added: “I’d come into the senior squad at 17 after I’d just changed over from Northern Ireland. It was the time I’d broken into the Everton team for the first time too, so the Ireland manager wanted to see me. That was a big step-up but I want to get back there as soon as I can.”