Test great Dennis Lillee fears England could exploit an ageing Australian batting line-up in the Ashes series.
Lillee (right) with Australia's star leg-spinner Shane Warne
Justin Langer will be 36 when the first Test starts, with Matthew Hayden, Adam Gilchrist and Damien Martyn all 35.
"It doesn't matter how fit an individual is, his reflexes are not going to get better as he gets older, so problems are harder to hide.
"Even the greatest players get tapped on the shoulder by Father Time at some stage," Lillee commented.
Langer responded in the best way possible, hitting 188 not out for his state side Western Australia.
And spinner Shane Warne said: "The age only comes into it if you are not performing.
"Since the Ashes we've won 11 out of 12 Tests so I think we've been performing OK."
Former fast bowler Lillee, 57, took 167 of his 355 Test wickets in Ashes contests, and always targeted older batsmen.
And he is concerned that Steve Harmison, Andrew Flintoff and Sajid Mahmood, who can all bowl at 90mph and above, will not shy away from testing out the Australian batsmen with short deliveries.
Australia have won 11 of their 12 Tests since being beaten 2-1 in England last year, surrendering their grip on the Ashes for the first time since 1989.
But writing in the West Australian newspaper, Lillee said: "Mark my word, the England pace attack, mentally buoyed and on faster Australian wickets, will this summer be at their absolute peak age-wise."
And he added: "I'm afraid there are danger signs for Australia as the most-anticipated Ashes series for years heads our way."