Kewell took a bad knock to his ankle in the Carling Cup game against Bolton last season yet still played 49 games for Liverpool in his debut season. However, he has since missed Australia's World Cup qualifiers against New Zealand, Tahiti and Fiji and Farina is worried about the long term effect if Kewell doesn't get a proper rest.
"Harry genuinely has a problem," said Farina. "He's only 25 and has the larger portion of his career to go. If he doesn't manage himself properly, his career could be cut short. Marco van Basten had to retire at 28 through an ankle injury."