"I have to be careful how much I talk about him as I must protect him and be cautious," said Allardyce, who took Morrison from United in January 2012, to the Daily Mail. "But, of course, I'm excited. There is nothing better than hearing people praise your players.
"Fergie just told me he needed to get Rav out of Manchester. That lifestyle and that group of people he was brought up with wasn't helping him. But he said I had a chance with him because he was an unbelievable talent.
"Certainly, we had early problems with him and his self-discipline and self-organisation. He just wasn't functioning properly. He was always late, his diet was bad.
"There was a time when I wondered if maybe it wouldn't work, that I couldn't do it with him. The problem was that he thought he was coming here to play in the first team. Then he wasn't in the team and he wasn't interested.
"Really gifted young players can lack the desire, edge and dedication. And that was Rav. It's a player's brain that makes him a top player. So we got him a loan at Birmingham and they had the same problem until they had injuries and he got in the team and stayed in.
"So he came back pre-season and from day one we were, like, 'Woah'. He has learned. He is tracking back, he is working. No longer walking.
"If I look at him, he is an 80 per cent different person. He walks in, he communicates, he isn't late as much. He is still late sometimes but they all are. But Rav is enjoying himself. I won't know how he reacts to being rested until it happens. It will be interesting.
"He will get mentally fatigued by the Premier League. It's a cauldron every Saturday. It's ferocious and unforgiving. On a young player that takes its toll."
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