FILE - In this May 11, 2014, file photo, Kei Nishikori. from Japan. returns the ball against Rafael Nadal from Spain, during the final of the Madrid Open tennis tournament in Madrid, Spain. Nishikori will participate in a sports and entertainment event hosted by Maria Sharapova in December, 2015 at the UCLA Tennis Center in Los Angeles. (AP Photo/Andres Kudacki, File)