Raducanu did not drop a set throughout the tournament in New York this month as she beat Leylah Fernandez to become the first British woman to win a major singles title for 44 years
Two-time champion Andy Murray, whose ranking has slipped to 118 as he battles to come back from hip surgery, will be aiming to win gold for the third Olympics in succession.
One of the biggest names in sport, Osaka stunned the tennis world when she pulled out of the Grand Slam on Monday after being fined and threatened with expulsion for declining to face the media after her first-round match on Sunday.
"After having some problems in my left foot for a while, I have decided to do a small procedure on it," Wawrinka said in a tweet accompanied by a picture of him on a hospital bed.
"Everything went well. I will be out for a few weeks but can't wait to start practising again soon."
