Swiss tennis star Roger Federer, arrives at Cape Town's, International Airport Wednesday, Feb. 5, 2020. Federer is in Cape Town South Africa, ahead of his match against Rafael Nadal to be held Friday. (AP Photo)

Roger Federer's 2020 season has been abruptly halted. After reaching the semifinals of the Australian Open, the Swiss announced on Thursday that he underwent knee surgery, and will miss the entirety of the U.S. spring and clay-court swings.

Fans will get to see Federer return in time for the grass season, most likely in Halle, but will miss him in Dubai, Indian Wells, Bogota, Miami and the French Open. Since he will not be able to defend an enormous amount of points (over 3,000) the 20-time Grand Slam champion will fall to around world No. 7 by the time he returns.

While ranking drops aren't new for the 38-year-old, who underwent left knee surgery in 2016 only allowing him to play seven tournaments that year, he'll be missed dearly. What are his chances when he comes back?