Former Scotland, Manchester United and Leeds defender Gordon McQueen has been diagnosed with dementia.
His family announced the news on Tuesday, saying the 68-year-old wondered whether his persistent heading of the soccer ball was a contributing factor.
McQueen, whose soccer career started at St Mirren before moving to Leeds in 1972 and later United, represented Scotland on 30 occasions, scoring five goals.
Having managed Airdrie during a coaching career that included time at Middlesbrough, the ex-centre-back went on to become a popular TV pundit in the UK.
"In January, Gordon McQueen, our dad, was formally diagnosed with vascular dementia," a statement released by his wife Yvonne, daughters Hayley and Anna and son Edward said.
"As a family we felt it was important to let people know, particularly if raising awareness can help others in similar situations.
"Whilst as a family we've found it hard to come to terms with the changes in dad, he has no regrets about his career and has lived life to the full.
"He had unforgettable experiences in his playing days with Scotland, Manchester United and Leeds United, and also took so much from his coaching and TV work in more recent times."
The family said football allowed McQueen to travel the world and experience things he could only have dreamed about.
But they said he wants footballers of today's generation to know there may be risks with persistent heading of the ball.
"Dad scored some important goals in his career and memorable headers but used to stay back in training, heading the ball to the goalkeeper for practice over and over," they said.
"He does wonder if this has been a factor in his dementia as his symptoms appeared in his mid-60s."
McQueen's former Leeds teammate Jack Charlton died with dementia last year and it was confirmed in recent months that English soccer great Sir Bobby Charlton has been diagnosed with the disease.
England's Football Association is currently supporting two independently led research studies examining former professional players for early signs of neurocognitive degeneration.