The tourists are a team in turmoil ahead of the fourth Ashes Test, desperate to salvage something from the series after relinquishing the urn in Perth.
Root, having been appointed earlier this year as skipper, finds himself under unprecedented pressure.
He has struggled with the bat, scoring 176 runs at an average of 29.33, and risks leaving Australia as England's worst-performing Ashes touring captain in 40 years.
However, it is Root's demeanour that has alarmed Ponting the most.
"The way he answered a lot of the questions after the game last week seemed almost like a little boy," Ponting said.
"You need to be more than that as a leader, especially when things aren't going well. It just looks like it has been a little bit soft."
Middle-order batsman Bairstow noted the team owed Root in the final two Tests.
"It's been pretty tough ... there's pressure on everyone but he's dealing with it absolutely fine," Bairstow said.
'South African' gets England call-up.
England paceman Tom Curran will make his Test debut in a forced change to the tourists' XI.
With Craig Overton out of the fourth Ashes match due to a cracked rib, Curran, uncapped legspinner Mason Crane, first-Test flop Jake Ball and 2015 Ashes winner Mark Wood were in the mix to receive a call-up.
Skipper Joe Root made a captain's call, backing the South African-born seamer to rattle Australia on a flat pitch.
Steve Smith slams 'rubbish' James Anderson sledge
Australian captain Steve Smith has branded Jimmy Anderson's critique of Australia's pace depth as "rubbish", while Joe Root has attempted to extinguish the spotfire created by England's all-time leading wicket-taker.
Anderson remarked last week Australia have "got problems" beyond their gun pace trio of Mitchell Starc, Josh Hazlewood and Pat Cummins.
"They haven't got much other than these three," Anderson said on a BBC podcast. Anderson was seemingly trying to make a point that pacemen capable of bowling at 150km/h are rare beasts anywhere in the world but it's been interpreted by Smith's side as a slight.
Especially on Jackson Bird, who will play in place of injured spearhead Starc in Melbourne.
Starc and David Warner both fired back at Anderson on Christmas Eve. Smith was more terse on Christmas Day but made his thoughts clear.
"That's rubbish to be honest," Smith said.
"Does he know that much about Australian domestic cricket? I'm not sure. I know there's plenty of guys who could come in and really do a job for us."
Root is yet to caution Anderson or seek clarification about the comments, saying he was only made aware of them recently.
