Last year 's runner - up Rafael Nadal withdraws from the French Open . Spanish player has already missed European and North American events . He lost to Novak Djokovic in last year 's final in New Haven . ( CNN ) -- Former world number one has a history of knee problems .
Last year 's runner - up Rafael Nadal withdraws from the French Open . Spanish player has already missed European and North American events . He lost to Novak Djokovic in last year 's final in New Haven . Former world number one has a history of knee problems .