Aldo told the Daily Record: “I had Jason as a youngster and you could see right away what qualities he had. He was exceptional.
“But he did have a few problems at Tranmere. He didn’t have the right people around him at the time. He wasn’t living his life in the right way as he should have as a young man.
“He got easily distracted and that stopped him going forward in many ways. Since Jason has gone to West Brom he has changed his lifestyle and in the last two years I’ve seen a massive improvement in the way he has gone about his job.
“Jason is far more consistent. He plays almost every game and is playing as I know he can in most matches.
“When he was a kid at Tranmere, Manchester United used to watch him play in every game whether it was the first team or reserves. He was seen as the next big star but as a young lad he just wasn’t focused enough.
“And boy, that was a frustration for me big time. I had Jason in my office more than any other player in all my years as a manager. To be honest he drove me mad.
“I tried to get through to him as I could see the potential the club had in this guy. But you can only have the same conversation so many times.
“Jason was just so easily distracted. I had him in the office at least once a week and he did respond to me. We had our moments but it’s the football I remember the most.”
Aldridge added: “I’d love to see him go to Celtic. That would be a great move for him.
“I actually thought Liverpool or Everton might go for him, even as a squad player. Because he is the kind who can come on and change games.
“He’s done it at international level with Wales and I’ve no doubts he could play Champions League. I once said he had enough natural ability which, if he could produce it consistently, would be good enough for Man United. I stand by that.”