Morrison, now 28, failed to maximise his potential at Old Trafford and recently left ADO Den Haag, the 11th club on his CV since leaving United.
Reading out Ferguson's text message, Ferdinand said: "Rio, my first impression of Ravel as a young lad was: 'He has always got time and space, always available to be on the ball, so unusual for a young lad of his age.'
"Give my regards to him please. Another thing about Ravel which I have always treasured because no other young player who made their debut did it.
"After the first game in the first team that he played the next morning he came to my office and gave me a letter thanking me for giving him his debut.
"I was gobsmacked, Rio. The boy had a good heart, he was just beaten by his background."
Morrison responded: "When I made my debut – words can't describe that, you know.
"Making your debut for Man United - it was only a minute as well.
"It touches you because if I could go back in time I would change 90 per cent of my life."
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