Australia's Kyrgios concedes tennis career could be over

The talented but temperamental 28-year-old had knee surgery a year ago, then aborted plans to return at Wimbledon after tearing a ligament in his wrist.

He withdrew ahead of the Australian Open as he continues to struggle for fitness, but is at the Grand Slam in Melbourne as a commentator.

He conducted the on-court interview after defending champion Novak Djokovic beat Taylor Fritz to reach the semi-finals on Tuesday.

Kyrgios said a career in the media was looking increasingly attractive.

"I sat down with my agent, Stuart Duguid, a couple of days ago to talk about my future," he wrote in a column for The Age newspaper in Melbourne.

"The reality is, there is a part of me that knows my time in the sport may be over. And I'm OK with that.

"It's a conversation that needed to be had. I'm at a crossroads in my career and have reached a point where life after tennis is a prospect that excites me.

"I could travel the world making really good money commentating on the sport... that's a life people wish they had."

Kyrgios, who reached a career-high 13 in the world in 2016 and has spoken previously of his struggles with his mental health, said last month he was "exhausted, tired".

He did not rule out a return to the court but said that after so many surgeries "my body may never be the same again".

Even if he does make a comeback, Kyrgios said playing at the Paris Olympics will not happen.

"One thing I will guarantee, though, is that if I am fit and ready to play, I won't be making myself available for the Olympics," he said.