By Julian Linden

SYDNEY (Reuters) - Australian fast bowler Glenn McGrath was keeping a low-profile on Thursday amid growing speculation he was about to follow Shane Warne into retirement.

Rumours have been rife in Australian media that McGrath is planning to follow Warne and quit after next month's final Ashes test in Sydney.

Warne confirmed his retirement plans at a news conference in Melbourne on Thursday but there was no word from McGrath or his management team.

Cricket Australia officials would not comment on the speculation but the fact McGrath has not denied the claims has fuelled the media's belief he will make an announcement in the next week.

The Sydney Morning Herald reported on Thursday that McGrath had abandoned his dream of pursuing a third World Cup title in West Indies next year in order to take care of his sick wife.

Jane McGrath was diagnosed this year with her third bout of cancer and has been undergoing treatment since.

McGrath took eight months off from the game to care for the couple's two young children before making his comeback in September.

He helped Australia win the Champions Trophy for the first time, then rejoined the test side for the Ashes.

McGrath's fitness played a pivotal role in the Ashes series in England last year. He was named Man of the Match after steering Australia to victory in the opening test but stepped on a ball on the morning of the second test and missed the game.

Australia went on to lose the series 2-1 and the Ashes for the first time in 16 years.

The 36-year-old McGrath has been troubled by niggling injuries for most of the past few seasons but remains as dangerous as ever whenever he is fit.

He took six wickets in Australia's first Ashes test win in Brisbane last month but struggled on a flat pitch in Adelaide and was noticeably sluggish in the field in Perth, where Australia regained the Ashes.

McGrath is third on the all-time list of wicket-takers behind Warne and Sri Lankan spinner Muttiah Muralitharan. With 555 victims, he stands alone as the most prolific fast bowler.