Former player and recent coach of Stefanos Tsitsipas, Mark Philippoussis believes that Nick Kyrgios' future in the sport is very much bleak after recent knee surgery.

Calling himself an expert on knee surgeries after having so many himself, he has first hand experience of what it takes to recover and he said that he can tell that he is far from being fit.

As well as that due to the nature of the injury, he is unsure how much he will even play on tour in the coming months. This after he lost terribly in Stuttgart then withdraw from multiple subsequent events including Wimbledon.

With the US Open on the horizon, attention will soon turn to that but he believes it will likely be a long term issue for the Aussie entertainer.

"He's not even close to being fit, and I knew straight away he was in trouble. If he comes back too early, which we have seen, and if he's not putting in the work physically on that knee to strengthen that joint, unfortunately I'm not sure how much we're going to see him," said Philippoussis.

"He's got to fear for himself. I've become a knee expert after six knee surgeries and it's something you can't mess around with. You're talking about your movement."My worry for him years ago was 'is he putting in the work physically?' and if he was to get that first major injury, I'm not saying it could be career-ending but it could be very dangerous if you don't put in that rehab work.

"I don't care how good your hands are, if you're not getting to the ball, and you're one-and-a-half, two steps slower, against any top-100, 200 player, it's going to be tough out there."