But O'Neill is only now ready to play him.
He said: "The fee the football club paid put him under pressure to perform. He has to put that to the side and get on with his game.
"He is very young but there was pressure on him to go and become an instant success. But he's got loads of time.
"He has the potential to be a really decent player and is working exceptionally well with Steve Guppy every single morning. He wants to do it, he has a strong appetite, and he is realising this is a tough old business.
"A few weeks ago, when Sheffield Wednesday asked about him, and a few others, I would have considered it because it would have great and particularly with the Under-21 games when his confidence is decent.
"But I have not had the where-with-all, so I hope he will come through here. I am hoping he can be the player he wants to be.
"We have had a number of conversations -, not recently, other than I said I thought he was doing very well in training to give him encouragement - and he is still very young but he is very strong in fact sometimes I don't think he realises how strong he is.
"He needs to add aspects to his game he maybe thought were there, but might have deserted him."