A member of the Celtic team from Lisbon, winner of the European Cup, asked for new tests on the possible links between football and dementia after two of his former teammates died a few days later.
Stevie Chalmers, who engraved his name in Celtic folklore when his skillful touch achieved victory over the Inter in the Portuguese capital in 1967, died at the age of 83, less than a week from team captain Billy McNeill.
Like McNeill, the father of six Chalmers had suffered from dementia in recent years.
Lisbon comrade Jim Craig said that further research should be conducted on the risks to football players and rugby players.
In a BBC interview with former Scottish rugby internationalist John Beattie, Craig said: "There should be some sort of detailed study into the fact that a player who is directing a ball and contact has something to do with it.
"When you go up for a high ball, you not only test the ball, you come into contact with your opponent's head for a long time.
"There have been some players who have had problems with dementia and really need to do an extensive series of tests and investigations.
"You wonder for a period of time that this causes some sort of damage that eventually leads to what we saw this week."
He added: "I recently bought a program at a gift shop and was West of Scotland against Hawick and actually listed the weights of the players.
"All the backs were ten, 11 stones and all the attackers were 12, 13, 14 stones. Now they have 17, 18 stones and the collisions are terribly difficult.
"You are destined to suffer some damage if this continues."
Other former professional footballers who have been diagnosed with dementia include the former England national Jeff Astle and the great Frank Deeee United Frank Kopel.
Chalmers overcame meningitis due to life-threatening tuberculosis at the age of 20 and became a professional footballer three years later when he joined the heroes of Celtic childhood.
Despite the late start, he scored 231 goals for the club before moving on to Morton and Partick Thistle.
Celtic manager Neil Lennon said that Chalmers "embodied the humility of the great team of Jock Stein".
CEO Peter Lawwell described it as a "particularly devastating time for the Celtic family" and conveyed his condolences to Chalmers' family and the Lions of Lisbon. Messages from former Celtic players and opponents, including Rangers and Inter Milan, who sent in their "deepest condolences".
Former Celtic striker Brian McClair shared his personal memories on Twitter.
"Stevie Chalmers was working for Celtic Pools when I arrived for my first day of training at Celtic Park in 1983," said McClair, who also played for Manchester United and Motherwell. "He left his office to greet me and wish me well and he told me, if I ever needed something, that I should go in. I was lost for words, a Celtic legend that did everything to welcome me. I was honored He was the mark of a humble and kind-hearted man. "