Ferguson told students in Glasgow: "I was part-time and in a reserve game against Airdrie I broke my eyebrow, cheekbone and nose and was out for months. They put this massive plaster cast on my face.
"After I came back from the injury I played three reserve games. We lost 8-1, 7-0 and 9-2. I said 'that's it - I am finished'. I took out papers to emigrate to Canada.
"On the Friday, my brother's girlfriend phoned up my manager at St Johnstone and told him I had the flu. But when I arrived home from a night at the swimming baths with my pals, my mother tore into me.
"She said, 'I've had a telegram from your manager - get down to the telephone booth and call him'. The manager said: 'Report to the Bath Hotel tomorrow, you're playing against Rangers'.
"I scored a hat trick and became the first player to do so against Rangers at Ibrox - it changed my life. I became a full-time footballer in the summer and never looked back."