Have top sports stars become impossible to manage? When Carlos Tevez, one of the world's highest-paid footballers, allegedly refused to play for his club Manchester City in a crucial European Champions League match in Munich, his manager, Roberto Mancini, was clearly outraged. But how do you manage strong characters who are also multimillionaires?
The problems aren't confined to soccer. England's campaign in the Rugby World Cup has been disrupted by stories about player misbehaviour, and manager Martin Johnson was forced to defend a group of his players after they were pictured drinking following their victory over Argentina. Johnson has also faced criticism for allowing players to go on a bungee jump.
As for Carlos Tevez, he has been suspended for two weeks pending an investigation into his conduct. Immediately after the game in Munich, Mancini said that the player was "finished" at Manchester City, even though he had been the club's top scorer in the past two seasons. Tevez has maintained that the incident arose from a "misunderstanding", but at present his public statements seem confusing, although he has seen no need to apologise. At first he said that he did not feel "right to play", but later he said the situation was caused by a mix-up on the players' bench.
Tevez's apparent disobedience has already provoked widespread condemnation in the media, and many other football managers have expressed strong support and sympathy for Mancini. Significantly, Manchester City's fans have turned on their free-scoring former hero, and almost all of them now seem to want rid of him.
But it is not as easy as that. Mancini, and the club, face a dilemma. Tevez has become an increasingly controversial character, who has long made it clear that he wishes to leave Manchester. In the summer, the club was willing to transfer him to the South American side Corinthians. The deal collapsed over money, and no other team was willing and able to afford such an expensive commodity.
A key legal question is whether a single refusal to play - if proved - can justify immediate dismissal for gross misconduct. Although not all sports lawyers agree, it seems likely that the answer is yes. Yet even if Manchester City are entitled to sack Tevez, they may be reluctant to do so, because of the risk of losing a multi-million pound transfer fee. Mancini is likely to be backed by the club's owners, but neither he nor they will be keen to take action that, in effect, gives Tevez what he wants.
Whatever the outcome of the Tevez saga, it illustrates the difficulty of managing top stars. Mancini is a highly experienced and successful manager, with a reputation for enforcing discipline, but even he has his work cut out trying to control a dressing room full of rich men who are accustomed to having things their own way.
As former England Rugby World Cup winner Ben Cohen put it to the BBC, "The professional players these days are a completely new breed... People want to be rock stars, everybody wants to be like a David Beckham." And whatever a written contract says, with the superstars, player power usually prevails.
So the likes of Roberto Mancini face quite a test in the public spotlight. Successful management requires commanding the respect of their players, the board and the fans alike. But there may be another factor to take into account. Superstars with big egos value their reputations. The almost universal condemnation and fury that has been directed against Carlos Tevez so far may prompt some of them to think twice before becoming involved in a similar stand-off with their managers.