Tennis great and current World No. 9 Roger Federer pulled out Tokyo Olympics 2020 due to knee problems. As one may recall, the 39-year-old had undergone a couple of knee surgeries in 2020 and had been recovering well. But once again the Swiss ace suffered from a setback with his knee. As a result, he had to pull out of the multi-event tournament. He took to social media and announced his withdrawal.