The January signing has now played five games since his switch from Swansea City but has yet to find the net.
O'Neill said: "He hasn't played that much but I am sure he would love to have come in and score goals immediately and win the fans over and play very well.
"At the moment both he and the side are coming to terms with the change of pattern of play and I have always said he will take time to settle.
"But I have no problems that he will get goals for us. Obviously he would like them as soon as possible but sometimes it happens. Steven Fletcher got off to a flyer and kept it going but Danny has not been that lucky, but there is time.
"I don't know him that well but I think he is one of those who cares about his performances by his participation in the team."