The return of U.S. striker Jozy Altidore, who had been sidelined by a hamstring injury, could help the Americans as they face off against a talented and young Belgian team Tuesday. Marcos Brindicci/Reuters /Landov hide caption

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Jermaine Jones and other members of the U.S. men's national team train in Manaus, Brazil. Fitness may be a crucial factor in the U.S.-Germany game on Thursday in Recife . Raphael Alves/AFP/Getty Images hide caption

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Comedian Will Ferrell was unveiled as the surprise "secret weapon" of U.S. Soccer, on the eve of a pivotal World Cup match against Germany. Ferrell promised to "bite every German player, if I have to." YouTube hide caption

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In this photo taken with a fisheye lens, members of the U.S. soccer team warm up during a training session the day before their Group G World Cup match with Ghana in Natal, Brazil. Julio Cortez/AP hide caption

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Midfielder Clint Dempsey of the United States dribbles the ball during a FIFA 2014 World Cup Qualifier match between Costa Rica and United States at Dick's Sporting Goods Park on March 22, 2013 in Commerce City, Colorado. Dustin Bradford/Getty Images hide caption

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