BIRMINGHAM: Shane Warne says Michael Clarke will shift to No.5 in the batting order for the fourth Ashes Test – and even the leg-spin great, a close friend and supporter-in-chief of the out-of-form Australian captain, concedes his place could be in jeopardy after this series.

Warne said on the final day of the third Test that it would be "ridiculous" to drop the out-of-form Clarke mid-series and selectors, saying they will give him as much time as he needs as they stare at a 2-1 deficit, will not do that.

In his column for Britain's Sunday Times, Warne predicted Clarke would turn the corner returning to his former batting position in the fourth Test starting on Thursday, which Australia must not lose or they will surrender the Ashes. There was a small admission, though, that Clarke's place could be in danger after the series if his troubles at the crease continue.

"Michael's performances are not due to any lack of preparation, and his position in the team is 100 per cent safe, until after this series at least, if not longer," Warne wrote.

"I believe that the fourth Test at Trent Bridge will turn out to be his moment. (Adam) Voges will make way for Shaun Marsh, who will bat at four with Clarke at five.

"This would have the double advantage of Clarke playing in a position where he has a good record and Marsh, the left-hander, acting as a useful buffer between two key right-handers - Steve Smith and Clarke."

Meanwhile, Warne's former partner in crime, Glenn McGrath, has gone from his customary prediction of a 5-0 series triumph for Australia fearing "the worst for Australia" if the pitch at Trent Bridge is similar to the seamer that was played on at Edgbaston. He believes Clarke and rest of the Australian team must adapt to conditions urgently or England will be celebrating an Ashes triumph by next weekend.

"Michael Clarke needs runs but I just cannot see Australia changing the captain midway through a series," McGrath wrote in his column for the London Telegraph. "If they lose at Trent Bridge then who knows what could happen but while the series is alive nothing is going to change with Clarke. I expect Shaun Marsh will come in and bat at four which would allow Clarke to go to five where he has done really well. Maybe if that happens we will see the old Clarke come out, especially if Marsh does well ahead of him."