Something suddenly clicks with fast bowlers. Occasionally it can happen at 22 if someone bowls like the wind, sometimes it takes little longer to become an overnight sensation.
For instance, Mitchell Johnson, from whom Australia expect so much this summer, has been around for yonks but he is 27 and it is five years since Dennis Lillee, who knows about such matters, described him as a once-in-a-generation fast bowler.
But Johnson found his game last winter. To the fast ball going across the right-hander he appears to have added an inswinger and it looks as though he can reverse swing it as well. In Graham Onions, England have also found a bowler who has found himself at last.
Onions, 26, has been among a crop of young fast bowlers who featured in selectorial thoughts for a few years: fast enough, fit enough. The door was closed by the insistence on consistent selection policy but also by not doing quite enough.
Last summer, Onions played a minimal role in Durham's charge to the County Championship and after suffering a heel injury was left out of the side for the run-in. But he took a long hard look at himself in the winter.
He had failed to gain selection for the England Lions tour which put him behind, at least, 10 other pace bowlers in the country. Onions, for once, had a proper close season and spent it working on his fitness and stamina. It has repaid him and he has taken five wickets in an innings five times including his 5-38 when bowling in a Test innings for the first time, against West Indies at Lord's.
Two weeks ago, he bowled Durham to victory by taking 7-38 against Warwickshire at Edgbaston, where the third Test will be played, and he is comfortably the season's leading wicket taker. Yet he seemed stunned to have been selected for an Ashes squad.
"It's absolutely unbelievable," he said. "I feel I have learnt a lot from the two Tests I have played and the Lions game just gone. It's quite hard to think from last winter that I'm in the squad and I just can't wait."
The selectors might easily have been swayed by Harmison's rousing efforts with the new ball for England Lions against Australia at Worcester last week. To watch him bowl was to be reminded of the enduring qualities which set him apart. He took four wickets in the Australians' first innings and twice bounced out their new boy wonder batsman, Phillip Hughes. But Geoff Miller and his panel, including the team coach, Andy Flower, will have considered three other matters.
First, there is the probable slow state of the pitch at Sophia Gardens. Second, they will have counted the number of false dawns into which Harmison has emerged over the years. Third, the form of Onions is self-evident, and he is capable of swing and skids the ball on.
Miller was rightly adamant in saying that Onions deserved his place. "He bowls very straight, bowls wicket to wicket, shapes it well and puts pressure on. He can bowl all day for you and if the conditions are right he can knock people over for you as well, especially against left-handers."
Although Harmison was the more eye-catching, Onions did his work well enough and dismissed Ricky Ponting with one that moved away. When Ponting described Harmison as having the attributes to be one of the all-time great fast bowlers, he was describing a player, it should not be forgotten, whose 221 Test wickets have cost 31.79 runs each.
But it is heartening not only that Harmison has returned to form but that he has worked so hard to do so. He needs bowling and he has bowled with fire and heart. It is also too often forgotten what a fine team man he is.
As he prepared to depart Worcester on Saturday night he knew he had been overlooked despite doing most of what could have been asked. But his thoughts were for his county team-mate.
"I can't speak highly enough of Steve Harmison," said Onions. "When he left the ground yesterday he said he was just a phone call away, which is great. He has played 60-odd Test matches and I have to look to him for advice. Steve has helped me so much in my career."
Onions is the man of the moment, however, and although he is not certain of his place in Cardiff for the first Test which begins on Wednesday, the selectors could easily decide finally that two spinners is simply too much of a gamble. They have picked a bowler in magnificent form and as he has a name that demands larking about with you could say that they have Onions but no tripe.
Know your Onions: The lowdown
*Age: 26. Born 9 September 1982 in Gateshead.
*Onions was first brought into the England squad in September 2006, replacing the injured Darren Gough against Pakistan in a one-day international series. However, Onions did not play in any of the fixtures.
*The right-arm medium-fast bowler took 7-39 in a one-day match for the England Lions against the Maharashtra Cricket Association in 2008, his best 50-over figures to date.
*Onions plays for Durham, for whom he has taken 40 wickets at 13.07 this season. He has a first-class career bowling average of 29.40, from 63 matches.
*He made his Test debut for England against West Indies on 6 May this year. He impressed, taking 5 for 38, including three wickets in an over.