Roger Federer, in Facebook message, on missing rest of tennis season: 'Considering all options after consulting with my doctors and my team, I have made the very difficult decision to call an end to my 2016 season as I need more extensive rehabilitation following my knee surgery earlier this year. The doctors advised that if I want to play on the ATP World Tour injury free for another few years, as I intend to do, I must give both my knee and body the proper time to fully recover. It is tough to miss the rest of the year'