An Ian McEwan-reading young chinaman bowler with two wrong'uns in his repertoire, who was rumoured to be perfecting a new delivery, magically tripped up a handful of batsmen at state level many summers ago. He had ex-Test legends for admirers. "My ambition," he said, "is the same as any cricketer… I want to play for Australia one day." After a forgettable afternoon against a touring side this chinaman bowler, this Dolman, disappeared, then two seasons later a glasses-wearing loan officer, Clifford, was acclaimed a Test batsman in the making, and an Ashes squad announcement was imminent. "I suppose," Clifford said, "I'm in with a chance. It would be good, for sure…"

The cricketer who dazzles early, not quite enough to get picked, and fades is an elusive, always wondering sub-branch of cricketer. Had only they been picked, might things have panned out brighter? They do not themselves know, and the thought can dog them. Sometimes the fade-out that happened was instant, total. Or it could have been a gradual dulling. Either way, the not knowing is theirs for life. We tend to assume that whatever small thing prevented them doing enough to get picked would also have inhibited them at the higher level for which they were striving. We don't, though, know this, no more than they do. But one player's still-active cricketing life gives us a half-open window.

Shaun Marsh completed his fourth Test series last week - "completed" in the sense that he was on the field, a small smile threatening to break out of his mouth, for captain Michael Clarke's victory speech in Cape Town, Marsh having ended the series out of the team after making 148, 44, 0 and 0 while he was in the team, scores that screech misprint, and scores characteristic of Marsh so far.

Marsh belongs to a rarer sub-branch: the cricketer who did not do enough to get picked yet is picked. It is strange there are not more of them. But selectors can be dogmatic, superstitious almost, about Test spots being not doled out until a player has dutifully piled up a mound of runs/wickets too big to see past. Occasional exceptions to this are part of well-established cricket lore. If a youngster of obviously stupendous talent rips a dashing hundred and, say, three utterly-at-ease 40s or 60-odds in a five-game-old career, that gives selectors a wildcard licence, it's enough for them to bank on. Or if a team is desperate, a player who has done nothing much yet looked classy while not doing it might sneak in.

But suppose a batsman was picked on the strength of one first-class hundred (a very, very dashing one) every two or so seasons. And what if, across an interrupted 15-innings span, he should proceed to score two Test centuries, plus three 0s for every century, and a 3, to boot, per century, with nearly no in-between scores? Marsh is that batsman. That is how rare he is: the cricketer who without doing enough to get picked is nonetheless picked, re-picked, picked again, and upon being picked proves beyond doubt he has what it takes then immediately sets about disproving it.

It could be coincidence, Marsh's curious stamp album of exotic scores and the unusual circumstances of his selection. Or it may be that when the standard processes of earned selection are bypassed something is lost. Some kind of accountability? Of reliability? We are in the land of conjecture. But selection is a conjecture-based field, and a riddle, being both an art of cricket - like batting, bowling, captaining, umpiring - and an art on which the textbook is no help. Superstition, I mentioned. Perhaps selectors go through their a-player's-gotta-earn-it checks and balances for a reason. They may not fully grasp the reason, but it's there, and it fuels a feeling, a hunch, that if a player is picked without having earned his place it might, or must, result in some lack of… stuff it, let's make the call: accountability.

Also, there's a chance a player's undeserved selection heaps pressure on him, cricket-wise, being-wise. In Marsh's case, it's in his voice, a laconic and friendly sounding voice, but always on the defensive, twisting positivity. He says "really" a lot, often followed by "well":

I wanted to play really well

I was really pleased with the way I went

I'm really looking forward to playing again

I tinkered with my technique and… it seemed to work really well

And the boys played really well

Boys: they are always "the boys", his team-mates, and considering his teams - Scorchers, Warriors, Kings XI Punjab, Glamorgan, Fremantle, Australia A, Australia - he has nearly enough boys to open a boarding school. Cricket's "a tough industry" and he knows he must "put runs on the board", a cliché that has outlived most of the world's Test grounds actually having wooden scoreboards. This is not meant to be mean. They all do blankspeak. Journalists' questions seldom give cricketers much chance to shine. When Marsh talks, we're on a road with no end yet no destination. And he's been on our screens for years now without us having an accurate fix on him. Him looking so much like his dad - that's another thing, and it only throws us further off the scent.

It cannot be dismissed as definitely nothing, the presence of his dad's green cap at home, on the bar, beneath glass, out of fingers' reach. When a Test is on, a ground and its grandstands are cluttered with old Test faces, and to Marsh they are familiar faces in a different way, in fact with some he was throwing ice cubes at them as a six-year-old in a victorious Old Trafford dressing room - wow. It might be a calming sensation, or an extra stress, or both.

Feel for the selectors, who hear voices saying make him earn it, whose own eyes swear he is in Australia's best six batsmen - so minimalist, pure, the illusion of faultlessness. If they require him to earn it and he never does earn it they won't ever be sure what's gone and might have been, and the window will be shut again, no comfort offered, no sting either, to the ranks of the always wondering. It is a puzzle.

Marsh, when asked to grapple with it, has said: "I don't really know."

Runs will right everything. Except he has made 'em before and they didn't.