The Liverpool star seems to be recovered from the broken foot he suffered back in February. He provides strength and leadership for Slovakia at central defense, and his health is critical to the team's success. Unfortunately, Skrtel injured his ankle in a June 5 friendly against Costa Rica. His status is pending.

Kewell has struggled mightily to recover from groin surgery in December of last year. He has increased his training and claims he will be fine come the Socceroos' first match. If he is unable to perform, it would be a huge blow to Australia as they would lose one of their two most important field players (with Tim Cahill being the other).

Swiss captain and star striker Alexander Frei injured an ankle in training just before the team's flight to South Africa and will have to await scan results to determine if he'll be able to play a part. Frei is one of Switzerland's most experienced and reliable stars, so losing him would be a big blow to Ottmar Hitzfeld's team.

Gallas was nearly left off France's final 23-man roster due to injury. He's back now, and seems to be fit, playing in France's final pre-World Cup friendly against China. The domineering Arsenal center back is a force on defense, and any relapse of injury would seriously weaken Les Bleus.

The Arsenal captain (though Barcelona has their eye on him) hasn't played since breaking his leg in April during a Champions League quarterfinal match. The midfielder insists he will be fit for the World Cup, but, as with Torres, Spain can absorb his absense with Xavi leading the deepest midfield in the tournament.

After missing five months with Arsenal due to an ankle injury suffered during an international friendly, Van Persie returned to the North London side in mid-April. He seems to be back to full fitness, having taken the field for Holland in recent friendlies. Still, the oft-injured striker is always a health concern, and any absense during the World Cup would be a serious challenge for the Dutch.

In somewhat of a surprise move, Xavi has seemed to put his club team ahead of his national team this year. Xavi played the end of the club season with a slight muscle tear in his calf, an injury that, according to Barcelona coach Pep Guardiola, "could cost him the World Cup." It seems that Xavi is fit and won't miss any time in South Africa, but if he is unable to perform at his high level at the World Cup, many will be left questioning his choice.

The 2007 FIFA World Player of the Year, Kaka has struggled with groin and thigh issues during his first season at Real Madrid. The Brazilian recently said he is not concerned about his fitness for the World Cup, but clearly his injuries are still, at the very least, in the back of his mind. His ability to take the field in every match will be crucial as Brazil faces tough competition in the so-called Group of Death.

Onyewu ruptured his patella tendon during a World Cup qualifier last fall. Despite recovering from that injury, he didn't play for club team AC Milan after that. "Gooch" has played in the team's friendlies leading up to the World Cup, but he hasn't shown the form that got him his deal with the Italian side. If he isn't at the top of his game, an already-shaky U.S. defense will be that much more fragile.

England's top striker first injured his ankle in the first leg of Manchester United's Champions League quarterfinal against Bayern Munich. Since that day in March, Rooney has struggled with the injury, while also picking up a nagging groin injury. He seemed to tweak something in England's first pre-World Cup friendly against Mexico, but coach Fabio Capello does not seem overly concerned with the health of his top striker.

The oft-injured Liverpool striker is once again a question mark for Spain. He underwent knee surgery in April and missed the remainder of the club season for the Reds. While Torres is rehabbing hard as he tries to get fit for South Africa, the Spanish team doctor recently said, "Right now, we cannot say whether Fernando will be ready in time for the first match against Switzerland." That being said, Spain does not have a particularly difficult group, and the team is talented enough to absord his loss for a match or two.

A consistent starter for coach Fabio Capello in midfield, Barry injured his ankle during a late-season Premiership match. He was estimated to be out 3-4 weeks, and has a spot on England's final 23-man roster. It still remains unclear when he will be fully fit to play.

Portugal takes a big hit with the loss of Nani, who has been ruled out with a bruised collarbone. Nani would have played on the left wing, opposite superstar Cristiano Ronaldo. Nani came on strong for Manchester United this season, finally fullfilling the potential Sir Alex Ferguson always claimed he had. For a Portugal side with plenty of holes already, Nani's injury will not help them get out of the Group of Death.

After a solid season with Chelsea and a Premier League title, midifeld star John Mikel Obi was expected to make the big leap internationally by leading the Super Eagles in South Africa. However, the young Mikel Obi had knee surgery and did not recover in time to play a part in this summer's tournament.
 

When the German captain went down with an ankle injury in Chelsea's FA Cup final victory, his country's World Cup hopes may have gone with him. The 33-year-old was expected to provide much-needed leadership for a young German side, but now coach Joachim Loew will have to hope his players grow up fast.

Bayern Munich's European hero was flying high entering this World Cup cycle, but a hamstring injury in a friendly against Hungary on June 5 has put the superstar winger's tournament in doubt. Doctors will work feverishly to put Robben back in a position to shine this summer in South Africa.

While the England captain suffered through back injuries all season long for Manchester United (as shown below), he seemed to be finally healthy heading into the World Cup. Not anymore. The central defender suffered a knee injury in training just a week before the start of the tournament, and has been ruled out for the World Cup. Huge blow for England.

With Michael Essien ruled out for the World Cup, Ghana's chances of making a deep run have taken a serious hit. They were already in a difficult group, with Germany, Serbia and Australia, and Essien's injury means that the African side will be without not only its best player, but one of the best midfielders in the world. They can still advance out of group play, but the challenge just got so much harder.

The is the biggest injury of the World Cup, hands down. Drogba is Africa's biggest star, and the best player on an Ivory Coast team that was trying to become the first African side to advance past the quarterfinals. What this does to both country and continent cannot be understated. What a terrible and tragic blow to the entire tournament if he cannot recover in time.