McGrath has struggled for form during the VB Series

Alderman said McGrath, 36 next week, would struggle to play all five matches and there was no obvious successor.

"If I was a selector I'd be pretty scared," Alderman said. "There's no ready-made replacement.

"He is a day-by-day, game-by-game prospect. Everyone has to realise that. It's a compact Ashes series."

I am not convinced that this time next year McGrath will be in the Australian team Terry Alderman

The five-Test series is to be squeezed into a gruelling six-week window.

Australia lost the series 2-1 in England last year, with both defeats coming when McGrath was injured, with elbow and ankle problems.

"If he does play in the first Test, he won't play in all five," Alderman told Sydney's Telegraph newspaper.

"I am not convinced that this time next year he will be in the Australian team. If he starts next summer, he may not be there at the end."

McGrath has taken 542 Test wickets, putting him third on the all-time list, and 331 in one-day internationals.

But he has struggled in the current one-day VB Series, taking only four wickets in five matches against Sri Lanka and South Africa.

Meanwhile, McGrath's long-time team-mate Shane Warne has played down speculation over a possible return to international limited-overs cricket.

Warne, 36, announced his retirement from the one-day game just before the 2003 World Cup but then missed the tournament because of a doping ban.

"Not at this stage no, I'm retired," the leg-spinner said when asked if he would be back for the 2007 World Cup.