Novak Djokovic.

Tennis world no. 1 Novak Djokovic withdrew Wednesday from competing in next week's China Open due to injury. 
The 29 year-old is suffering from an elbow injury this season from as early as the Wimbledon final he played this summer. He said that doctors advised him not to play in tournaments until his condition improves. He expressed his hope that he will be ready ATP World Tour soon. 
Djokovic's injury, if prolonged, could give hope to Andy Murray of overtaking the Serb's position as the top-ranked player by the end of the season. 

Source : XINHUA