It is not the first time the Kewell camp have made such claims, following the player's own attack on the Leeds medical staff prior to his departure for Liverpool in 2003.
Kewell spent 13 years in England from 1995, the majority of which came at Elland Road where he was a key component in Leeds' Premier League heyday of the late nineties and early noughties.
Hot property: Liverpool pipped Europe's elite clubs to the signing of Kewell
Withdrawn: Kewell didn't make it to half-time of the 2005 Champions League final because of injury
However, he was offloaded as part of club's fire sale in the wake of relegation. Kewell joined Liverpool but was blighted by a succession of injuries, never scaling the heights that had once led to a reported £20+million bid from Inter Milan.
The Australian limped out of both the Champions League final in 2005 and the FA Cup showpiece a year later; the latter injury, a torn a groin muscle, kept Kewell sidelined for almost a year.
The 31-year-old has since resurrected his career at Turkish club Galatasaray, but continues to be hampered by fitness problems. According to his agent, though, he is now in the best possible hands after being allowed to return to Sydney for treatment.
'The reason he gets treated out here [in Australia] now is because we have the best medical staff in the world,' Bernie Mandic told the Sydney Morning Herald. 'He lost three-and-a-half years of his career at Liverpool because the guys over there in England had, quite literally, no idea what they were talking about.
'You have to wonder what they're doing over there. Perhaps they're trying to protect their reputations, but they're certainly not trying to protect their players.
'I think it's a disgrace, as I think it was a disgrace the way Harry was treated.
'What goes around comes around, and people are now wondering, 'How has he recovered like that?' when everyone in England thought he was a broken toy.
Stricken: Kewell suffered a series of injuries at Liverpool
'It's a damn shame we didn't come here earlier. If nothing else, the last World Cup would have seen a far better Harry and maybe they could have avoided the [foot] injury he suffered in the end.'
'But that's life, you learn from it, move on, and that's exactly what Harry's done. Now he doesn't take any chances. He likes to get second opinions, and the bottom line is that Australian doctors have never let him down.'
Ironically, Liverpool - who are believed to have thought Kewell would never make a full recovery - are now trying to track down the Australian specialists who brought him back to full health.
'We had Rafa Benitez call him the other night inquiring who these guys were because Fernando Torres has got such major problems now,' Mandic said.
'Then we've had Jonathan Woodgate's physio, Dave Hancock, who used to work at Chelsea and before that worked with Harry and Jonathan at Leeds, inquiring about Jonathan, who is apparently almost unfixable.
'Look at Liverpool - why is it that over so many recent years, usually around November, lots of their key players are injured?
'It's always soft-tissue injuries. How come other clubs, like Arsenal, don't have that sort of a dilemma? And why do their players recover quicker? There's logical reasons for all of this.'
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