The pace bowler has secured 309 wickets in 71 appearances with an stellar bowling average.
Australia's chief selector the selector has declared that pace spearhead Cummins will play a "major part" in this winter's historic rivalry.
Rumors had circulated that the 32-year-old might sit out due to a persistent back stress problem that was still troubling him.
Previous updates from the Australian camp suggested no final decision had been made regarding whether he would play, with the Test matches kicking off on 21 November in the WACA.
Bailey expressed that Cummins is "building up" and remained hopeful about the prospects of being involved.
"It's clear that the window is narrowing and there are permutations around that, not only his injury, but other factors as well," the selector added.
"It's positive. We firmly believe that he's going to play a key capacity. Ideally starting in Perth. Should that not happen, we'll adjust."
Injury History
He was sidelined the ODI and T20 games against New Zealand and India last month after scans revealed a lower back issue.
Previous incidents include of spinal problems, with recurrences in 2012-13, 2013-14 and 2015-16 forcing him out of three Australian summers in a short span.
He emphasized he would be bold in recovery efforts in his rehabilitation process to make the squad for the Ashes.
The selector indicated that it was unclear if Cummins had begun bowling as part of his recovery but conceded it was "becoming urgent" for him to regain fitness for the initial match.
Backup Options
If he's unavailable, ex-skipper Smith will lead the side.
The talented all-rounder was withdrawn recently from the national team for their limited-overs matches against India as a safety move because of discomfort in his torso.
The selector characterized it as a "slight concern and confirmed that he's scheduled to appear in the state-level matches, so will be "well-prepared to deliver overs."
"Extensive planning has gone into creating the schedule for him to participate for the first Test as an batting and bowling option," he elaborated.
"His involvement was limited to the initial matches anyway. The way he swings the bat in limited-overs, should it hinder progress for another day, we opted to approach this more conservatively."
Series Schedule
The Historic Rivalry
21 November 2025 - 7 January 2026
