File this under the biggest 'what-ifs' of Pakistan cricket. It is probably not as intriguing as "What would Mohammad Zahid had been like, had he not been injured" but Mohammad Amir's career, or what's left of it, still remains one of the most puzzling questions for cricket fans.

What if he had stayed within the line, both proverbial and the fading white on that fateful summer day at Lord's? What kind of career would he have had, had what happened had never happened? Would he have become the best fast bowler in the world ... or even history? With him spearheading their attack, could Pakistan have fared better at the 2011 and 2015 World Cups?

These are questions that do not bother cricket fans anymore, but they should. For, we're talking about a 15-year-old who was handpicked by the great Wasim Akram himself. This was no ordinary talent but someone who at 17 was starring at World T20s, clocking 152kmph and making the ball do things that no underage fella ever should. As a slender 18-year-old, he was bowling five-wicket maidens against Australia at the World Cup.

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At 18, he was also bagging five-wicket hails in Test matches against Australia in Australia and helping beat England in England. Oh yes, the talent was real, and potential enormous. Our memories may not serve us well but even the hazy remnants of the cricketing zeitgeist are enough to remind us that this was a once-in-a-generation-kind find. The kind that isn't made but born.

A true wunderkind of his ilk had perhaps not been seen since Sachin Tendulkar took guard in Karachi in the autumn of 89.

Then the summer of 2010 happened.

Fast forward five-and-a –half-years later, and Amir was back. Still just 24, he was supposed to continue where he left off. What happened was nothing but a minor pothole on a journey towards an otherwise successful and fruitful career, they said. Except that no pothole that erases five years of an athlete's career can be a minor pothole. It's more like a grand canyon.

A shadow of his former teenage self, 27-year-old Amir, who should now theoretically be in his prime, appears more in his twilight. The pace, the movement, the zing ... it can still be seen but only in glimpses.

We saw it in his hat-trick during Pakistan Super League 2016, we saw it in that Asia Cup spell against India, and we saw it again against India in the Champions Trophy final. But that's pretty much it.

In the three years since he's been back, those three matches are all he's had that are reminiscent of the young Amir of the old. This new, older Amir doesn't compare.

Whatever he had has left him. And it makes sense too. There is a precedent of high level athletes struggling to regain former levels following years of inactivity. Mike Tyson had lost just one of the first 42 fights of his career when he was convicted of rape and sent to prison. He won just nine of the 16 bouts he fought after the four years (91-95) he spent behind bars. Some say the great Muhammad Ali, too, had lost a step during his near four-year hiatus.

Of course there are always exceptions but for most top-level athletes, and especially for a fast bowler, the discontinuation of training regime and deprivation of competition work together to cause a permanent loss of ability. That precisely has been the case with Amir 2.0.