From Roger's website:
I’m extremely disappointed to announce that I will not be able to represent Switzerland at the Olympic Games in Rio and that I will also miss the remainder of the 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. However, the silver lining is that this experience has made me realize how lucky I have been throughout my career with very few injuries. The love I have for tennis, the competition, tournaments and of course you, the fans remains intact. I am as motivated as ever and plan to put all my energy towards coming back strong, healthy and in shape to play attacking tennis in 2017.
Thanks for your continued support.