When world No. 1 Roger Federer pulled out of the final Masters Series event of the year in Paris on Monday, he inadvertently opened up old wounds and an even older debate.
For some time now there has been a raging debate over the ability, or maybe willingness, of the top tennis players to compete in the biggest tournaments.
When Federer, who complained of fatigue after his title victory in Basel on Sunday, joined world No. 2 Rafael Nadal and No. 3 David Nalbandian in pulling out of the ninth Masters event, the disappointment among the organizers was palpable.
It sparked an immediate response from both them and the new ATP chairman Etienne De Villiers.
They must have known it was coming following Federer's comments on Sunday after his Basel victory:
"I'll wait until Monday, I've got to give myself a day of thought," the Wimbledon, Australian Open and US Open champion said.
Federer had won his last three events played over the last four weeks -- including 10 matches in a row to lift Madrid Masters and Basel Open in successive weeks.
"I've played a lot. This is my 92nd match of the season, I have to be careful," he said. "It all depends on how I feel."
The Masters Cup in Shanghai begins just a week after Paris ends and for players like Federer, who has won three Grand Slams, four Masters and 11 tournaments in total this season, the season-ending finale figures far higher in his priorities than Paris does.
A look at his reason for withdrawal conjures suspicions at first when comparing him with other players.
Nadal pulled out with a stomach injury and David Nalbandian cited gastroenteritis as his reason for a no-show. Both of them have already qualified for Shanghai, though, and may well be expected to turn up fit and well there.
But while Federer complained of fatigue, that looks a somewhat hollow excuse when comparing his tournament record to someone like Russia's Nikolay Davydenko.
Federer has played in 17 tournaments this year, while Davydenko is lining up in his 31st this week in Paris, and he plays more Davis Cup matches than Federer as well.
But although playing almost twice as many tournaments, Davydenko has actually played four fewer matches and he is approximately 10 clear of anyone else on the tour. Even Nadal has played only 67 matches compared with Federer's 92 in the same number of tournaments.
But it is not just the playing time that is energy-sapping, the travel too can be a burden. And that is where Federer, and Nadal, can cut down compared with their peers.
Assuming Davydenko traveled directly from one tournament to the next, never going home and never having any skewed stopovers, he would have covered 110,000km in flying back and forth to 31 tournaments and Davis Cup matches.
It all points to an incredible amount of endurance needed to be a professional tennis player, physically and mentally, which is why De Villiers is determined to push through changes.
"I am both deeply disappointed and concerned by the depletion in the player field for one of ATP's most prestigious events," he said after Federer's withdrawal.
"Unfortunately this is the third year that withdrawals and injuries have hurt the event and the fans' opportunity to see all their tennis idols," De Villiers said.
"This reinforces my determination to introduce meaningful change to the calendar, the structure, the incentives and sanctions needed to have healthy, motivated top players grace our top events," he said.