RIO DE JANEIRO (AP) -- Elite professional footballers may be pampered like royalty, but near constant training and grueling club and country commitments are taking their toll on the World Cup before the tournament even kicks off in Brazil.
Germany midfielder Marco Reus on Saturday became the latest player to pull out of the global football showcase, joining the likes of Frank Ribery, Radamel Falcao, Theo Walcott and several other big names who will be watching the World Cup in between trips to the doctor or physio.
Dutch coach Raymond Verheijen, who has in the past helped condition Netherlands, South Korean and Russian players for European Championships and World Cups, has long been a critic of over-training and blamed it for increasing injuries.
He said national coaches need to wind back the amount of training they put their squads through at the end of long club seasons.
''Their players are still fit, but they are tired,'' he told The Associated Press in a telephone interview. ''Players have to rest. It's the opposite of club preparations at the start of a season.''
He called the intensive training regimes of many national coaches ''Russian roulette,'' saying that overtraining is a key cause of muscle injuries.
Football is, of course, a fast and physical sport and not all injuries can be attributed to exhaustion, but many of the stars at the World Cup had barely finished their club seasons when they had to report to rigorous national training camps. Any lingering aches and pains they accumulated have no time to recover.
Former Sunderland manager Paolo Di Canio told Gazetta dello Sport that England's campaign in the strength-sapping heat of Brazil will likely suffer due to the Premier League's non-stop season.
''They do not have a winter break,'' Di Canio said. ''It's nice to play at Christmas, but they pay the price for this in June when the fatigue can be devastating.''
Brazil coach Luiz Felipe Scolari said he has not considered resting Neymar or any other players because of the recent wave of injuries.
So-called ''friendly'' tune-up matches in recent weeks have also shattered plenty of World Cup dreams.
Reus twisted his left ankle while challenging Artur Yedigaryan in the first half of Germany's friendly against Armenia - part of the team's buildup to the World Cup in Brazil.
''The strange thing is that they've all been traumatic injuries, '' Italy defender Giorgio Chiellini said of injuries to Reus and midfielder Riccardo Montolivo, who broke the tibia bone in his left leg last weekend during a warm-up match with Ireland.
England midfielder Alex Oxlade-Chamberlain's World Cup is in doubt after he sustained ligament damage in his right knee during a friendly against Ecuador in Miami Gardens on Wednesday.
Nevertheless, Verheijen says such matches are vital to coaches in forging one team out of players from several different clubs.
''They have to build up rhythm,'' he said.
Sometimes, players can be one another's worst enemies. Netherlands winger Arjen Robben was furious at a hard tackle from behind by Ghana defender Rashid Sumaila last month. Friendly games are often far from friendly, as Brazil and Serbia showed in a feisty game on Friday.
''I'd have liked to hit him, but you can't do that,'' Robben, who was not injured, said after the match.
The lengthening list of absentees from the World Cup starting in Sao Paulo on Thursday would form a strong world all-star team.
News of the partial ligament tear in Reus' left ankle came a day after France winger Franck Ribery pulled out of the tournament after failing to overcome a back injury.
Monaco striker Falcao was left out of Colombia's squad after failing to recover from a knee injury.
Netherlands coach Louis van Gaal said he had to jettison his preferred 4-3-3 formation after key midfielder Kevin Strootman wrecked his knee playing for AS Roma.
Among other players absent from football's greatest stage:
-Belgium striker Christian Benteke ruptured an Achilles tendon in April.
-Mexican midfielders Juan Carlos Medina, who injured his ankle during practice three weeks ago and Luis Montes, who broke his right fibula in a match against Ecuador last Saturday.
-Croatia lost its only left back Danijel Pranjic during a friendly against Australia.
-Spanish goalkeeper Victor Valdes tore the anterior cruciate ligament in his right knee in March.
-Veteran Netherlands midfielder Rafael van der Vaart is out with a calf muscle injury in his right leg.
Some potential stars of the Brazil tournament are weary and hurting but determined to play on.
Portugal's Cristiano Ronaldo resumed training Saturday after recovering from tendinitis and a muscle injury, both in his left leg.
Ivory Coast coach Sabri Lamouchi says that Yaya Toure, star of Manchester City's English Premier League-winning team, has a leg injury and is fatigued but is expected to play.
Robin van Persie, striker at Toure's crosstown rival Manchester United, will also be playing despite a sore groin.
''It is not an injury, but he can feel it. He has been feeling it for a long time,'' Van Gaal said after the Netherlands' first training session in Rio.
Playing through the pain barrier is the norm for players like Van Persie, the Dutch captain and top scorer.
''He plays with it and he has always played with it,'' Van Gaal said. ''Every player has pains.''
Associated Press reporters covering teams in the World Cup contributed to this story.