Ben Stokes’ shoulder injury has forced a reshuffle in the side, with fellow all-rounder Sam Curran recalled at Roy’s expense and Chris Woakes returning in place of Craig Overton.
England can still salvage a drawn series over the next five days and will be eager to deny Australia turning their unassailable 2-1 lead into a first series win on these shores since 2001.
Standing Roy down at his home ground was not how England envisaged their experiment with the World Cup-winning batsman ending but an average of 18.70 in his five Tests, with a top score of 31 against Australia, left him vulnerable.
Roy faces an uncertain future in the red ball game as a result but whether he earns a second chance – either at opener or in the number four position he filled at Old Trafford – could depend on who succeeds head coach Trevor Bayliss, whose four-year reign ends after the series.
“Jason is the unfortunate one to miss out,” said Root, after explaining Stokes would effectively play as a specialist number four batsman.
“He is very aware of where he is at and what he needs to do to get himself in the best place to perform in Test cricket. He’s had an opportunity to come in and play Test cricket, get a feel for it, and it has not gone quite how he would have liked.
“But I’m sure he will go away and work extremely hard and come again. That is what you expect of guys when they get left out and I’m sure he will have that attitude and want to try and prove a point and get himself back into the side.”
Roy is far from alone in under-performing with the bat and serious questions have been asked of Joe Denly, Jonny Bairstow and Jos Buttler over the past few weeks.
All three average fewer than 26 in the past four Tests, the kind of return that does not win Ashes series and one that puts them firmly under the microscope.
Root’s own captaincy has been queried, though there does not appear to be any appetite for change from within the England camp, and he made it clear his plans for the future do not have room for those who cannot raise their game.
“I think in terms of personnel things might change, as they have done for a while. We have to focus on the core group of players that can lead this team forward,” he said.
“In terms of my own captaincy I know the direction I want to take this team moving forward and it is about starting that now and not after this series. It is important we win this game and have a really strong winter and move forward as a group.
“You are playing for your country: that’s the fundamentals of it. We have got some very passionate guys who are very proud to represent England and however you motivate yourself, whether it’s getting yourself on a winter tour or trying to get yourself a hundred or five-for, I think it’s really important to harness that this week and take it forward.
“But, ultimately, being part of a national team is a carrot in itself.”
Woakes’ return, conversely, appears more of a reflection on Overton’s abilities than an admission that last week’s selection was a mistake.
Overton batted with admirable defiance in the day five rearguard, frustrating the touring attack for 105 balls before being last man out, but looked a step down on Woakes with ball in hand.
“We brought Craig in for those Old Trafford conditions and he also had a back spasm within the game, which is a slight concern going into another Test,” said Root.
“He did a fantastic job and he should be really proud of the way he went about his business. I’m sure it’s not the last we’ll see of him.”
Root took the opportunity to pay tribute to Bayliss and suggested the Australian’s self-assessment of his own tenure, pitched at “five out of 10”, was under-selling his contribution.
“I give him a slightly higher mark. I think that sums him up really, he’s quite a modest bloke,” said the skipper.
“He has had a massive influence here and he will be sorely missed by all the players that have had a chance to work with him.”
Provided by Press Association Sports