The world No.52 strained a muscle in his back training in Melbourne and while the injury is minor, his camp isn't willing to risk his health at the round robin event in Perth before the first major of the year.

Scans on Wednesday allayed fears he may have suffered a stress fracture, and Larkham is confident the 19-year-old will be back on court training within a few days.

Kyrgios was one of the main drawcards for the Hopman Cup, where he was set to represent Australia alongside Casey Dellacqua. Matt Ebden will replace him.

"He's going to have to pull out of the Hopman Cup, but he's going to be fine for [the] Sydney [International] and the Australian Open," Larkham said.

"He's just slightly strained a muscle in his back, we can't risk the Australian Open.

"He's borderline, he probably could have gone out and played [Hopman Cup] but if he had a real tough match he could wreck it and not play Sydney or the Australian Open."

It's a blow to Kyrgios' Australian Open preparation, which was hampered last year when injury forced him to miss lead-up tournaments in Brisbane and Sydney.

Cramp then robbed him of any chance of victory after winning the first two sets against Frenchman Benoit Paire in the second round of the Australian Open.

After a breakout year including his stunning Wimbledon upset of Rafael Nadal, Kyrgios ended his year prematurely with bone stress in his arm in September.

"We've been training hard because it's really important he can go the distance physically," Larkham said.

"He's got the ability, we've been doing long sessions and at times he's been pulling up stiff and sore.

"I'd like to think it won't affect him too much, he'll probably have four or five days off and build up into Sydney.

"He needs those matches in those legs so he doesn't pull up stiff the first match of the Australian Open, he hasn't played a tour match since Malaysia in September.

"It's disappointing for the tournament, but you can't risk missing a major and the physios are fairly confident he'll get it right."

Former Australia star Mark Philippoussis says Kyrgios has all the weapons to be one of the best tennis players in the world and a grand slam contender.

Back in Australia for the first time in six years, ahead of playing in the Australian Open Legends tournament, Philippoussis has been keeping an eye on the progress of Australia's current tennis crop, including teenagers Kyrgios and Thanasi Kokkinakis, who both share his Greek heritage.

Philippoussis, who reached a career high No. 8 in the world and lost two grand slam finals, predicted Kyrgios would rise to the top of world tennis if he could stay fit.

"He's an incredible talent, he has all the game, all the weapons to become one of the best in the world and definitely a grand slam contender," he said. "Being a big guy like that it's very important to train in a smart way and keep as healthy as possible."

Philippoussis is no stranger to expectation, given he beat then-world No. 1 Pete Sampras as a 19-year-old at the Australian Open in 1996. But his advice for Kyrgios and Kokkinakis was "to keep the mind on track and stay on course".

"What followed, I wasn't prepared for," Philippoussis said of his shock win over Sampras as a teenager. "I was a 19-year-old local kid with the home crowd on my back, and I rode that wave, I played one of the best matches of my life that night, and it was incredibly difficult for me to come back down from the clouds after two days and play my next match.

"Tennis is a beautiful sport but it's also a sport where you get thrown out onto the world and it's on an international level. As an athlete and as a human being, you're learning, you're a kid, growing up in the public eye is not easy. They're going to have a lot of support and they should take advantage of that."

Philippoussis said the Greek heritage he shares with Kyrgios and Kokkinakis was a source of pride. "Number one you're an Aussie but you've always got your heritage in the background," he said. "They should be incredibly proud of who they are ... it's great to see some names with some longer letters."