Imagine Wayne Rooney telling Roy Hodgson he didn't want to go to the World Cup and then, a couple of weeks before England take off, demanding inclusion because he had been "listening to his heart" and now wants to go.
And, even more improbably, imagine the England manager dropping a player from his 24-man squad to bring back his one true star.
Well it might not happen in football but it certainly has in rugby league where Sonny Bill Williams, who has a better claim than anyone to be called the world's best rugby player in either code, has just arrived on these shores with the holders New Zealand for the World Cup, which starts next Saturday.
Williams is the uniquely controversial master of three sports and will almost certainly be the face of a tournament which desperately needs all the stardust it can sprinkle. Originally left out of the 24-man squad because he was thought to be re-signing to play rugby union with the Waikato Chiefs, SBW performed a back flip equal to anything he has achieved on the field. Anyone else would have been told politely – or maybe not so politely – to get lost, but Sonny Bill, in this as in so much else, is a special case.
"He is the difference between losing the World Cup and winning it," said the former Kiwi coach, Frank Endacott. His captain, Simon Mannering, would not go quite that far. "But he's a player who can have a lot of influence on the game," he says. "As for him coming back into the squad – things change."
Mannering does not believe that the sense of togetherness which a succession of Kiwi coaches have nurtured and elevated to the status of a philosophy is jeopardised by the special treatment for Williams, although he confirms that the final decision was made by their current coach, Stephen Kearney, essentially on his own.
"He talked about it to the boys, but really it was a decision for Steve to make. The main thing was that he was coming back for the right reasons." The return of his prodigal is a timely boost not just for the Kiwis, but for the tournament as a whole.
Shaun Edwards, who coached Wales in the rugby union World Cup against Williams and the victorious All Blacks, calls him "the biggest name in world rugby, in either code. He's the kind of player you want to watch, so it's great that rugby fans here will have the chance to see him".
Not so great, perhaps, if your name is Tohu Harris. The Melbourne forward was the player axed from the squad when Williams had his change of heart. "I feel shit about it, to tell you the truth," Williams told the BBC in New Zealand. So bad, in fact, he offered to stand down again – but inevitably the Kiwis were having none of that.
Those close to him say that he will draw strength from the idea that, in some way, he is now doing it for Harris. Steven Price, who played with him at his first club, the Canterbury Bulldogs, and is still a close friend, says that is the way he will approach it. "If anything that makes him even scarier," Price said. "He's a huge inspiration to the boys in the New Zealand team."
Mannering admits: "It's hard on Tohu missing out, but he's dealt with it well and he will have his chances to play for his country in the future."
Looked at in the broader context, this is just the latest example of Sonny Bill doing what he wants to, regardless of what anyone else thinks. The most glaring case of that – and the one that has continued to define him in many people's eyes – was his walk-out from Canterbury, shortly after signing a new contract, to take up a mega-bucks deal with French rugby union club Toulon. Words like "treachery" were bandied about and a poll in a Sydney newspaper declared him the most hated man in Australia – ahead of the Bali bombers.
It was also the birth of the "Money Bill" Williams image. When he went to play rugby union in Japan, it was "Sushi Bill". Even the star of the New Zealand women's team gets called "Honey Bill" Hireme. He has entered the vocabulary.
Nor did he endear himself to everyone in Australia and New Zealand when he converted to Islam in 2008, a year after a series of alcohol-fuelled misadventures. That was widely assumed to be a result of the influence of his personal manager, Khoder Nasser. SBW became the first Muslim to play for the All Blacks.
In the middle of all this, he found time to launch a boxing career. After winning his first six bouts, he was ranked as New Zealand's leading heavyweight, although that side of his sporting commitments appears to be on the back-burner for now.
When he returned to his original code after more than five years away, there were those who doubted if he could get his rugby league career back on track. His form for the Sydney Roosters, however, has been compelling. Two weeks ago, he was a major factor in them winning the Grand Final and was awarded the Clive Churchill Medal as man of the match.
Still, nobody knew if he would play in the World Cup for New Zealand, for Samoa or not at all. But that's Sonny Bill; you never quite know what he's going to do, on or off the field.
Like others who played in the Grand Final, Williams will sit out the warm-up game against the Cook Islands at Doncaster this afternoon. He will be in the side a week later, however, when the Kiwis launch their World Cup defence with a clash against the Samoans at Warrington that could produce one of the highlights of the tournament.Such is the overlap between the two squads that there is an element of the "mate against mate" State of Origin flavour about the game.
The defending champions are relieved that, for all the complications he brings, Sonny Bill Wiliams will be on their side. For the rest of us, having him here at all is a result.
US pull off pre-tournament shock
The United States, widely expected to be the World Cup whipping boys, pulled off a shock defeat of France 22-18 in Toulouse, leaving the home side in pre-tournament disarray.
After largely controlling this warm-up match through their captain, the Parramatta stand-off, Joseph Paulo, the Tomahawks clinched their country's best-ever result with a late try from their full-back, Kristian Freed. The victory is a major boost for the new American coach, Terry Matterson, formerly in charge at Castleford. It was all the more remarkable for being achieved without their three most experienced players: Clint Newton, Ryan McGoldrick and the recent Wigan signing Eddie Pettybourne.
All three are expected to be available for the United States's first match of the tournament proper, against the Cook Islands at Bristol on 30 October.
A France squad, led by the Wakefield Trinity coach Richard Agar and built around the successful Super League club, the Catalan Dragons, has a demanding first match against Papua New Guinea at Hull KR next Sunday.