The UK's Brexit Secretary David Davis, a veteran Eurosceptic, reportedly faces losing the top job to a pro-EU ally of Prime Minister Theresa May, it emerged on Friday 1 June.
Cabinet Office minister Ben Gummer, who said he felt "sick to the pit of my stomach" about the impact leaving the EU would have on British jobs, is being lined-up for the promotion as part of a post-election reshuffle, The Times said.
Davis, meanwhile, could replace Vote Leave cheerleader Boris Johnson as foreign secretary.
Gummer, the MP candidate for the Conservative marginal of Ipswich, currently sits on the Home of Commons' Brexit Committee and apparently played a key role behind-the-scenes in putting the Tory election manifesto together.
A pro-EU campaigner, Gummer told the Ipswich Star last year: "I cannot disguise the fact that this will be a very, very difficult time – and there will be effects for my constituents."
The reshuffle news comes just a day after May, who also unsuccessfully campaigned for Remain, claimed "you can only deliver Brexit if you believe in Brexit".
"This is the prize – the opportunity that is within reach," she said. "A stronger, more secure and prosperous nation. A brighter, fairer future for all.
"That is what excites me about the years ahead. What I am working towards. What motivates me to do what I do and put myself at the service of ordinary working people.
"And it's what makes the decision you face next week so vital. This election so important. Because make no mistake, not everyone shares this view.
"They say we're too small and too insignificant. That Britain can't do it. That the British people are not up to the task.
"In short, they don't believe in Britain. And if that's where you start, you have no hope of getting the right deal for Britain in Europe. You can't negotiate the right Brexit deal for Britain if you don't believe in Britain.
"You can't fight for Britain if you don't have confidence in our strengths and in all that we have to offer. You can only deliver Brexit if you believe in Brexit. You can only fight for Britain if you believe in Britain.
"You can only deliver for Britain if you have the strength, the plan and the determination to see it through."
The general election is less than a week away on 8 June, with the latest opinion from Panelbase, of more than 1,200 people between 26 May and 1 June, giving the Conservatives an eight point lead over Labour (44% versus 36%).