"I don't think Robbie works hard enough at the skill factor of football," Gradi told the Sunday Mercury.
"He might not thank me for saying that, but it is intended as a compliment not a criticism.
"Robbie has allowed the personality side of his game to take over and I think he should concentrate a little bit more on the football side of things because he is a good player.
"He has only developed this character since he left us.
"I had Robbie when he was a kid at Crewe and he was terrific. He was the best of our under-13s by far and when he left to go to Manchester United, while I was disappointed, I kept tabs on him and finally bought him back.
"On his return he didn't show the same skill he had showed at that younger level but he was still a good player and I thought he would get that back.
"I remembered he was small as a kid but when he came back he told me he was now six foot and could run for ever.
"You don't have to be quick if you can run like that and I knew he could play football and use both feet. I also knew that nothing was going to faze him and he had a good character."
"But Robbie himself has probably not quite realised just how good he can be.
"Martin O'Neill also said the same thing at Leicester and we both feel he could be a better player than he tries to be."
