Between any two World Cups, there is a lot of turn-over of the competitors.
Of the 209 nations eligible, only 32 actually make it through continental qualifying to the final stages of the competition. Hence, many of the teams you may have gotten used to seeing at the 2010 World Cup in South Africa might not be making the trip to Brazil in 2014.
So who will be the unlucky teams who will go from competing in the world's biggest competition in 2010 to watching at home in 2014?
Here are the nine nations from 2010 most at risk of missing out in 2014.
Okay, this one is kind of cheating.
I mean, North Korea have already been eliminated from qualifying and are the first team from South Africa sure to miss out on Brazil.
They could not duplicate their Cinderella run through qualifying for the 2010 and were eliminated very early in the Asian process.
In 2010, South Africa only qualified for the World Cup because they were the hosts of the competition.
Once in the tournament, Bafana Bafana became the first hosts ever to not advance through the group stage.
Now, the South Africans are sitting in third place in their group (when only one advances), behind the Central African Republic and Ethiopia.
It will be a tough enough task to get through this stage, but even if South Africa can turn this around and win the group, they will still need to win a two-legged playoff against another African team.
Don't be too surprised if you don't see South Africa in Brazil.
Remember when Slovenia was giving the USA that terrible scare in the group stage in South Africa? Well, that was quite some time ago for this country.
To start their qualifying campaign last month, Slovenia suffered two awful losses to Switzerland and Norway. Now, they sit last in what looks to be the easiest group of the UEFA process.
Do they have time to turn this around? Of course.
However, Slovenia hasn't shown many signs to indicate they are ready to come back and navigate their way to Brazil.
Well here's a surprising one.
In the quarterfinals of the 2010 World Cup, Paraguay had a penalty to open the scoring against eventual champions Spain. If they had made it, who knows what would have happened from there. Instead, they missed and Spain went on to a 1-0 victory.
The Paraguayans backed that fine showing by playing well in the 2011 Copa America, defeating Brazil in the quarterfinals and working their way to the final. There, they suffered a 3-0 drubbing to Uruguay that seems to have sent them into a tailspin.
Now, Paraguay sits in dead-last in the South American qualifying group, eight points out of a mere playoff spot.
These South Americans desperately need to turn things around very quickly to even have a shot at making it to Brazil.
Coming into the current stage of Asian qualifying, the expectation was for Australia and Japan to run away with their group and automatically qualify for Brazil.
Instead, the Australians have played poorly and currently sit in fourth, one spot shy of just the playoff spot.
I would still expect the Socceroos to make it to Brazil, but they are one or two poor performances away from missing out on the World Cup.
You might remember Algeria from the incredible goal Landon Donovan scored against them in stoppage time to send the USA through the group.
However, what you might not have realized is that they were one of only two teams not to score a goal in that competition.
Now, they have one of the toughest groups in the African qualifying campaign, having to compete with Benin and Mali.
I would not be surprised if Algeria doesn't even make it through this group and to the last round of qualifying.
Here's the other team from South Africa not to score a goal.
Honduras currently sits in second place in their group, which would be good enough to get them through to the final round of qualifying. However, they are level with third-place Canada and are the only team to have faced Cuba (the worst team left in North American qualifying) twice.
There is a good chance Canada will be able to turn this around and eliminate Honduras by next week.
Plus, even if they don't, Honduras will have to work their way through the hexagonal.
In 2010, Ghana were a Suarez-handball away from becoming the first African team to make it to the World Cup semifinals.
Unfortunately, things have taken a turn for the worse for Ghana in qualifying for 2014.
They were grouped with the reigning African champions, Zambia, who they lost to in the second round of matches. Luckily, Sudan's victory over Zambia meant that all three teams were tied after two matches.
However, FIFA found that Sudan had fielded an ineligible player against Zambia and thus overturned the decision and awarded the victory to Zambia.
Hence, Ghana now sit three points behind the current African champions and have four matches to make them up.
It will be a tough task. Ghana has no room for error.
Have you noticed that, except for England, every team the USA played in 2010 is on this list? (Plus, England is by no means a lock)
So it should come as no surprise that the United States is on this list.
Don't get me wrong: I will be rooting for the USA this week. However, these next two matches are some of the biggest in the USA team's history.
One slip up will mean the end of their World Cup bid, setting the sport back ten years.
Two wins and they are off this list and probably headed to another major tournament.
The importance of these matches against Antigua and Barbuda and Guatemala cannot be stressed enough.
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