World number one Roger Federer became the latest and most prominent withdrawal at this week's Paris Masters when he pulled out on Monday due to exhaustion.
The top seed, who celebrated a first title in his home town in the Swiss Indoors tournament in Basel on Sunday, is expected to return for the Masters Cup from Nov. 12 to 19 in Shanghai.
The withdrawal of the dominant Swiss, who has never won in the French capital and misses the event for the third year in a row, means the indoor tournament is now without five of the world's top six players.
"He (Federer) called us this morning to tell us he was extremely tired," said tournament joint director Alain Riou.
"Now we have to ask ourselves questions and use all our weight to make sure decisions are taken.
"Years without any decisions added to conflicting interests have led to that sort of situation," he added.
World number two Rafael Nadal pulled out on Sunday with a stomach muscle injury, joining world number three David Nalbandian, four Ivan Ljubicic and six Andy Roddick.
The highest-ranked player left in the draw is world number five Nikolay Davydenko.
NO SANCTIONS
Federer, Nadal, Ljubicic and Roddick have already qualified for the season-ending Masters Cup and probably all felt they needed a break before going to China.
"To organise the Masters Cup in China shortly after the end of the European indoor season causes problems," Riou said.
The official said Federer would not be sanctioned because the rules allowed him to miss two Masters Series a year and Paris was only his second no-show after he missed Hamburg.
"We have the greatest respect for Roger Federer and we have no complaints about his attitude," Riou said.
"He was ready to come here to answer questions from the media and to pass a medical but we told him there was no need."
The tournament's other joint director, Cedric Pioline, did not blame Federer either but said measures were needed to make sure the top players entered the showcase series events.
"The tournament organisers seem to have more obligations than the players," said Pioline, a former top 10 player.
"We need a system with sanctions and, having been a player, I can tell you that fines don't work. We need bans."
