LONDON, England (BBC) – England are set to take a major gamble in the crucial fifth Ashes Test by replacing Ravi Bopara with the uncapped Jonathan Trott, BBC Sport understands.

Ian Bell, whose place has also been under threat, is set to keep his place and move up the order to number three.

Mark Ramprakash and Rob Key had been touted for call-ups for The Oval.

But Trott has now been left out of the England Lions team to face Australia, adding to the speculation that he will win a Test start against the tourists.

England, who must win the fifth Test to regain the Ashes, are set to officially announce their squad today after a week of intense debate about the make-up of the squad.

The 28-year-old Trott was included in the 14-man squad for the fourth Test at Headingley, but was released to play for Warwickshire.

With 1 013 runs in the County championship this season at an average of 92.09, Trott is a player in a rich vein of form – but the decision to throw him in for a Test debut in the high-pressure environment of a decisive Ashes clash is a big gamble for the selectors.

The South Africa-born batsman served a timely reminder of his ability with a century for Warwickshire against Nottinghamshire at Trent Bridge, while Bell made 126 to help his case to retain his place.

Yorkshire’s Joe Sayers has taken Trott’s place in the second-string Lions side against Australia in a two-day match at Canterbury starting yesterday.

Bopara’s place has been in severe jeopardy, with just 105 runs from his seven innings in the series.

He showed his fighting spirit and ability with an unbeaten 52 for Essex against Middlesex on Friday, but it appears to have been insufficient evidence for the England selectors.

Nevertheless, England coach Andy Flower has backed the 24-year-old – who had been in fine form against the West Indies earlier in the year – to come through his difficult spell.

“Every batsman has been through a run of low scores and he hasn’t managed to really get in and show what he is made of in this series,” said Flower.