The £13 million-plus (Dh75.9m) Ghana international striker is currently with the UAE club on a season-long loan deal after securing a move in September.
That agreement was made three months before O'Neill succeeded Steve Bruce, the man who had signed the 26-year-old Gyan from the French side Rennes, and although there was talk of a return to Wearside in January, the agreement between the clubs did not allow for that.
Last month Carlo Nohra, the Al Ain chief executive, said: "We must activate the purchase agreement [with Sunderland] by the end of April.
"Obviously we need to sit down with the player and work out his plans before then. The sooner he decides the better as all parties can then plan for the future and make alternative arrangements"
Gyan has two years remaining on his contract, and while any decision on his future is yet to be finalised, O'Neill has suggested it may not lie with him.
He said: "The situation is, I believe it was a year-long loan for a start, for which they had to pay us some money of the transfer fee which we paid in the first place, and that is still in existence.
"There was some talk between all parties in January that didn't come to anything. I wasn't party to those conversations, although I was kept informed of them, of course.
"I think it will be the end of the season before I can assess anything."
While it would be no real surprise if Gyan did sever his ties with Sunderland, it would leave the Black Cats once again searching for a prolific scorer.
Amid mounting speculation over potential targets and possible departures, O'Neill said he is yet to speak to Ellis Short, the owner, about summer signings.
He said: "I haven't considered it and I certainly haven't had an opportunity to speak to a very important man at the football club who happens to own it."
Meanwhile, the Black Cats head into today's Premier League clash with bottom side Wolves with the fortunes of the clubs having differed markedly since they last met on December 4.
That day, O'Neill sat in the stands at Molineux and saw the team he was about to take over lose 2-1 despite taking the lead and squandering a penalty. Wolves went three points ahead of their visitors that day but have since claimed just eight more, while Sunderland have amassed a further 31 to secure their place in the top flight.
O'Neill said: "I have to say I was obviously very concerned coming in.
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