Stevie Chalmers, who etched his name into Celtic folklore when his deft touch secured victory over Inter Milan in the Portuguese capital in 1967, died at the age of 83, less than a week after the team’s captain Billy McNeill.
Like McNeill, father-of-six Chalmers had been suffering from dementia in recent years.
Fellow Lisbon Lion Jim Craig said more research should be carried out on the risks to both footballers and rugby players.
In a BBC interview with former Scotland rugby internationalist John Beattie, Craig said: “There should be some sort of detailed study into whether a player heading a ball and contact has got something to do with it.
“When you go up for a high ball, not only do you head the ball, you make contact with the opponent’s head a lot of the time.
“There have been a few players who have had problems with dementia and they really have to do an extended series of tests and investigations.
“You do wonder over a period of time that it causes some sort of damage that eventually leads to what we have seen this week.”
He added: “I picked up a programme in a souvenir shop recently and it was West of Scotland v Hawick and it actually listed the weights of the players.
“All the backs were ten, 11 stone and all the forwards were 12, 13, 14 stone. Now they are 17, 18 stone and the collisions are tremendously hard.
“You are bound to get some sort of damage if that goes on.”
Other former professional footballers who were diagnosed with dementia include ex-England international Jeff Astle and Dundee United great Frank Kopel.
Chalmers overcame life-threatening illness tuberculosis meningitis at the age of 20 and became a professional footballer three years later when he joined boyhood heroes Celtic.
Despite the late start, he scored 231 goals for the club before moving on to Morton and Partick Thistle.
Celtic manager Neil Lennon claimed Chalmers “epitomised the humility of Jock Stein’s great team”.
Chief executive Peter Lawwell described it as a “particularly devastating time for the Celtic family” and passed on his condolences to Chalmers’ family and the Lisbon Lions. Messages came in from former Celtic players as well as opponents, including Rangers and Inter Milan, who sent their “deepest sympathies”.
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 came out of his office to greet me and wish me well and told me, if I ever needed anything, that I should pop in. I was lost for words, a Celtic legend going out of his way to welcome me. I was honoured. It was the mark of a humble, good natured man.”