Nick Kyrgios. Photo: Paul Kane
There are concerns Nick Kyrgios' knee injury could be as bad as Rafael Nadal's.
Kyrgios has been forced to pull out of the World Tennis Challenge in Adelaide with a patella tendon issue.
3AW's Doc Larkins says these injuries are notorious.
"Rafa Nadal was dogged by this injury for 4-5 years," Dr Larkins told Sports Today.
"It's an overuse and overload injury.
"Going into a Grand Slam is not the sort of thing you want to be doing when you're trying to reduce load."
Nadal, a 14-time Slam winner, had his dominant spell interrupted by his troublesome knee.
He has not passed the quarter-finals of a Slam since winning the French Open in 2014.
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