Men's football is the red-headed stepchild of the Olympic Games, especially now that baseball is gone. Unlike every other sport, in which the best athletes in the world are competing at the highest level, men's football is an Under-23 competition with three over-age players allowed.
This does a lot to avoid what would be a very sticky mess between Olympic teams and club football teams regarding the release of players. Barcelona was furious when Lionel Messi went to the 2008 Olympics, even though he was only 21 years old.
This time, there's good news for teams with young Argentinian players on their books: Argentina didn't qualify. There hasn't been a lot of controversy this time around, but clubs will still be stewing in rage about losing their best young players, even if they do so silently.
The Clear Favorites - Brazil
Because of the recent youth movement in Mano Menezes' squad, along with the rapid improvement of Brazil's domestic league, the Brazilian Olympic team looks a lot like their senior team. First-choice players Neymar, Leandro Damiao, Oscar and Sandro are all under-23 players, and they're joined by over-age players Hulk, Thiago Silva and Marcelo, who are among the best in the world at their positions.
Their bench options are almost too ridiculous to be real. Every other team would love to have under-23 players as good as Lucas Moura, Romulo, Alex Sandro, Danilo, Alexandre Pato and Paulo Henrique Ganso, who Brazil can bring on as game-changing substitutes.
And perhaps even more importantly than all of their talent is the fact that this team has played together all summer in preparation for the Olympics. Menezes left senior players off of his squad for senior team friendlies earlier in the summer and has been playing with an Olympic team in both senior and under-23 friendlies since early June. In addition to being the most talented team, they will be one of the most prepared.
Spain went out to Brazil in the quarterfinals of last year's Under-20 World Cup, but otherwise, it's been a banner couple of years for Spanish youth football. They won the UEFA Under-21 championship last year and the UEFA Under-19 Championship this year. They won Euro 2012 with some great young talent in their ranks as well. That depth (and their long Euro campaign) is probably why they didn't take their best players as over-age players, but they did bring along three members of that Euro 2012 winning side. Over-age players Juan Mata and Javi Martinez will anchor the team, along with Jordi Alba, who does not count as an over-age player. Forward Adrian Lopez is the team's third over-age player.
Barcelona and Athletic Bilbao provide most of the team's top talent. Martinez should strike up a strong midfield partnership with club teammate Ander Herrera, one of the best passers in Spanish football. Keep an eye on right back and captain Cesar Azpilicueta, who could be making a big-money move away from Marseille if he has a great tournament.
Uruguay would have fielded a team that could contend for a medal if they took average over-age players, but they've pulled out the big guns in an attempt to go for gold.
First-choice senior team players Luis Suarez, Edinson Cavani and Arevalo Rios join a strong young side that can challenge Brazil and Spain. Young stars Gaston Ramirez and Sebastian Coates are the other big names on the squad, while 19-year-old right back Ramon Arias is poised to make a European move sooner rather than later.
Related: 2012 Olympics: Women's football tournament preview
The Hosts (And Medal Contenders) - Great Britain
Great Britain's squad doesn't stack up to Brazil, Spain and Uruguay, but they do have a strong team and will have the benefit of playing in front of a home crowd in every match. Most of the players in the team have played regularly in the top flight of English football, though there will be second division players in the starting XI. Both of the team's goalkeepers have never played in the Premier League, and even the most accomplished of the under-23 players haven't been regular contributors to top-flight teams for very long. Only Daniel Sturridge, Tom Cleverley and Aaron Ramsey have extensive top-flight experience.
Veterans Ryan Giggs and Craig Bellamy are expected to start, along with over-age defender Micah Richards. If their one warm-up friendly match is anything to go on, Swansea midfielder Joe Allen is going to be a key player for the side, and how he controls (or doesn't control) the midfield is going to be crucial to Great Britain's success (or lack thereof).
Stuart Pearce played with a makeshift back line that was specifically designed to defend against Neymar in Great Britain's friendly against Brazil and it didn't work. James Tomkins struggled and Micah Richards, supposedly the team's calming presence at the back, wasn't much better. Great Britain will struggle to get by Uruguay and the quarterfinal round if they don't get their defense sorted out.
The Dark Horses - South Korea, Mexico
South Korea hasn't made it to the semifinals of the men's football tournament as long as it's existed in its current format, but they put up a good showing every year. They've either made the quarterfinals or been within one point of doing so in every single tournament. All of their players are accomplished professionals, and they have played together at this level for a very long time. All three of their over-age players have played more than a dozen times at the under-23 level and six of their under-23 players have played at least 10 times at this level.
Mexico have had their Olympic team in training for a long time, playing multiple friendlies since June. All of their players are first team regulars in the Mexican Primera with the exception of Giovani dos Santos, who is on the books at Tottenham Hotspur in the Premier League. They will be just as prepared and well-gelled as Brazil when they take the pitch, but it's anyone's guess whether or not they can stack up against top competition outside of North America. Many of these players have destroyed MLS teams in CONCACAF Champions League and held their own with South American teams in Copa Libertadores, but this will be the biggest test of most of these players' young careers.
The Rest Of The Field
Senegal - Might have a good shot at getting out of another group, but they will struggle to get past Great Britain and Uruguay in Group A. All but one of their players is a professional in Europe, and their best player is probably Copenhagen's Dame N'Doye.
United Arab Emirates - While I have never seen any of these players play, I am confident that they will not be able to get out of Group A.
Gabon - Not expected to get out of Group B, but they do have one superstar that could spring them to some upset results. Striker Pierre-Emerick Aubameyang is arguably the best player in this group and could will his team to results by himself.
Switzerland - In a similar situation to Senegal. They could get out of an easier group, but it's tough to see them getting by South Korea and Mexico. Though, it certainly wouldn't be a massive upset if they pulled it off. Switzerland was unable to bring most of their best youngsters to this tournament, and would be favorites to get out of the group if they had Xherdan Shaqiri and Granit Xhaka. The best players they were able to bring are left back Ricardo Rodriguez and winger Fabian Frei.
Belarus - Some of these guys play regularly for a very decent BATE Borisov team, so they're not likely to get totally waxed. They could very will finish second in Group C. Their best player is Renan Bressan, an attacking midfielder.
Egypt - Will contend for second place in a wide-open Group C. After Brazil, there's not much separating the three other teams. They're boosted by their overage players, who are very accomplished senior internationals. Ahmed Fathy, Emad Moteab and Mohamed Aboutrika are some of the best players in Africa.
New Zealand - Probably the weakest team in the group, though their overage players should give them a fighting chance at second place. Shane Smeltz and Ryan Nelsen were linchpins of the team that drew three games at the 2010 World Cup. They have some decent under-23 players from the Championship and A-League, but this is not a strong squad.
Honduras - It wouldn't be too shocking if Honduras got out of Group D, though Japan probably have a better side. The team's three MLS players are all solid, as are Wigan's Maynor Figueroa and Montagua star Johnny Leveron. Mario Martinez is also a solid senior team regular.
Japan - The favorites to finish second to Spain, even though Japan has fared poorly at the Olympics in the past. They did not take any of their stars as over-age players, and will probably lean heavily on Takashi Usami.
Morocco - There certainly isn't a lot of depth here, but the best players in this squad are very strong for this level. Houssine Kharja is a Serie A veteran, Omar El Kaddouri had a strong season in Serie A as well, and Abdelhamid El Kaoutari helped Montpellier to a Ligue 1 title. However, the man to watch in their games is a youngster, 19-year-old Zakaria Labyad, one of the best young talents in the world. They should be able to challenge Japan and Honduras.