On 2 September 1972 Green suffered a knee cartilage injury that ultimately ended his professional football career the month before his 26th birthday. His competitive career at Newcastle lasted only 39 games (33 in the league) spanning 11 months in which he was idolised by the Geordie fans. Green later said of the injury, "I was finished at the age of 25 by a tackle from Crystal Palace's Mel Blyth but I honestly think it was an accident, not malicious. Nowadays I would have been out for a month to five weeks because I would have been in hospital the next day. However, in the seventies I was in a splint for six weeks running up and down the St James' Park terraces and was then allocated a general surgeon, the club vice-chairman Bob Rutherford, instead of an orthopedic surgeon."