The Gateshead-born striker has not scored in 10 games since his move from Swansea City - or in his final four games for the South Wales side.
Di Canio said: "I know what is going on with a player who normally scores goals. It is normal for him to score in every two or three games.
"I can talk to him to use his quality and encourage him but I don't need to go too deeply and convince him. I can see him every day in a good mood, he is very positive with the way we go through the drills.
"He is always the one trying to persuade his team-mates and encourage them because he is so active, not passive. He is not down.
"I am sure he is going to be crucial in the last three games, not only because it is easy to say he is the only striker I have. But I am sure the time will come when he will score and I am sure it will be in the next two games."