The 21-year old Nigerian attacking midfielder joined Killie on a two-year deal at the start of January after making just two appearances during his one-year stay with Celtic.
The former PSV Eindhoven man was once rated as a player to watch by FIFA and Shiels has urged him to now prove himself on the senior stage.
"I would class Rabiu as a player we can develop," he told SunSport.
"I think Rabiu's career is on the descent and I don't want to give him any discouragement when I say that. But he needs a kick-start - and I feel we can provide that.
"That tells you something. But, for whatever reason, his career hasn't taken off.
"People in the game and scouts I've spoken to have said Rabiu has great potential.
"But I don't want to be sitting in four years' time describing him the same way - as having potential.
"He has to start fulfilling that now. And if we can get him to his maximum potential, then we've got a good player.
"The first thing we have to do is make him feel comfortable. To give him an environment where he's going to develop."