Rafael Nadal, who won his first gold medal for the men's singles match at the 2008 Beijing Olympics, will not be defending his champion status during this summer's London Olympics. In an announcement made on Thursday, the Spanish tennis ace confirmed that an aggravated case of tendonitis in his knee is the cause of his withdraw.

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"I do not find myself in a condition to compete," the 26-year-old said, adding, [It's] "one of the saddest days of my career as one of my biggest ambitions, that of being Spain's flag-bearer in the opening ceremony of the Games in London, cannot be."

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The last big win for Nadal was defeating Serbian tennis pro Novak Djokovic, 25, at the French Open on June 10.

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Now that Nadal has stepped down from playing in the Olympic men's singles tournament, the No. 1 seed will be 2012 Wimbledon champ, Roger Federer, followed by No. 2 Djokovic and No. 3 England's Andy Murray. USA's own Serena Williams is the No. 4 seed for the women's singles.

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This article originally appeared on Usmagazine.com: Rafael Nadal Withdraws from 2012 London Olympics