Upul Tharanga was once the future. He stood tall and tranquil at the crease, had shots through the offside so beautiful that entire stadiums bawled when he drove, and he had the Kumar Sangakkara stamp of approval.
Eventually, though, oppositions began to study him. A technical flaw to the angled ball outside off stump was exposed. For entire series, Tharanga became like an usher at a film theatre, forever directing the ball to its proper place in the hands of slip. He was dropped when he went 14 innings without a fifty, and would not play Tests again for another seven years.
There have been some valuable contributions in his stuttered second coming, but where - if talent was the only consideration - Tharanga should have about 100 Tests on his timesheet, and close to 10,000 runs to his name, he finds himself asked to open the batting again, and at 32, still needing to prove his worth.
Cautionary tale number one.
Lahiru Thirimanne was once the future. He has the temperament of a monk, senior teammates said, and well, just look at that bent-kneed cover drive. There was an attractive 91 at an SCG Test. He floated through heartening ODI hundreds as well. Throughout, he had the backing of men like Aravinda de Silva.
But then, eventually, oppositions began to study him. Questions were asked of his technique. That iron temperament was put to the Test, and through late 2015, and the first half of 2016, Thirimanne became a global leader in tortured innings and low scores. He now finds himself out of the team and as yet unable to make a case for reintegration into international cricket.
Cautionary tale number two.
Kaushal Silva was once the future. No one had laboured so much to gain a Test place, and in an age where Sri Lanka batsmen were thought to play too many strokes, his stoicism was much regarded. He gritted his way to a good 95 in Dubai, and hit important twin fifties at Lord's.
Then opposition attacks came for him, and he went meekly with them into a long lull. Occasionally there would be another of those gutsy big scores, but these were infrequent, and his average was in retreat. At 30, he is now dropped from the Test team, not even an A team position thrown his way in compensation.
Cautionary tale number three.
Dinesh Chandimal was once the future. He didn't quite have the classical sensibilities of other young batsmen, but here is a man who has found a homespun technique that works for him, you thought. He bashed his way to encouraging overseas fifties and threw his every atom into the sweep shot at home. Along the way, he played some transcendental innings, became T20 captain, and made the populist decision to forego the IPL to work on his batting at home.
But then, of course: that familiar stagnation. He struggled with the bouncer in 2014, and was packed off to the Sri Lanka A team in the middle of a Test tour. He has been jerked around the batting order as well, and found himself often accused of surrendering his wicket without a fight.
He may yet have an outstanding career, but what is clear is that despite his blinding talent, international batsmen his age have leapfrogged him. At 27, he could be part of the Kohli-Root-Williamson-Smith conversation, yet instead he has recently been told by the chief selector to go back to club cricket in order to rediscover form.
Cautionary tale (sort of) number four.
Two young batsmen in the Sri Lanka squad find themselves at the end of the first portion of this well-trod journey. At 22, Kusal Mendis has hit one of the great Sri Lankan innings, batted with rare freedom on away tours, and has been the primary driver of optimism for fans of Sri Lanka. At 25, Dhananjaya de Silva was the best batsman in a famous victory over Australia, and has tamed Mitchell Starc as well as anyone in international cricket has recently managed.
Both have potential, but are coming off a tough series against South Africa, and in any case, have not found the consistency that will see them regarded among the world's best.
Their coaches can teach them plenty. They'll learn from repeated exposure to the world's best bowlers, from playing in the planet's most vaunted venues, and from doing battle in matches that are intense as they come. For some lessons though, they need not look much further than their own dressing room. Having talent is fine, but to harness it: that is the thing.