Rafael Nadal said he won\'t return to competitive tennis until an exhibition tournament in December in Abu Dhabi. Nadal, No. 4 in the world, will miss the rest of the ATP calendar, including the year-end Barclays ATP World Tour Finals. He is one of four players who had already qualified for the eight-player invitational event. Nadal hasn\'t played in a tournament since a loss to Lukas Rosol in the second round at Wimbledon. He passed up the Olympics and the U.S. Open, citing a partial tear of the patella tendon in his left knee. He won the French Open and was the runner-up at the Australian Open in the other Grand Slam events this year. Novak Djokovic and Andy Murray, second and third, respectively, in the world rankings, are already confirmed for the Abu Dhabi exhibition.