The pace bowler has secured 309 Test scalps in 71 Test matches with an stellar bowling average.
Australia's chief selector George Bailey has confirmed that skipper Cummins will play a "major part" in this winter's historic rivalry.
There were concerns that Cummins might sit out due to a persistent back stress problem that remained unresolved.
Earlier indications from the squad suggested no final decision had been made regarding Cummins' participation, with the Test matches set to start on November 21 in the WACA.
He revealed that Cummins is "building up" and was "optimistic" about his chances of being involved.
"We're aware that time is getting short and multiple considerations involved, not only the back issue, but other factors as well," the selector added.
"We're encouraged. We firmly believe that he will feature a key capacity. Hopefully starting in Perth. If not, we'll adjust."
Past Concerns
Cummins was ruled out Australia's limited-overs series against both Asian and Trans-Tasman rivals last month after medical tests showed a stress reaction in his back.
Previous incidents include of back injuries, with recurrences in 2012-13, 2013-14 and 2015-16 forcing him out of three Australian summers in a short span.
The bowler mentioned he would be ""aggressive" and "take risks" in his rehabilitation process to secure his spot for the contest.
The selector indicated that it was unclear if Cummins had begun bowling as part of his recovery but admitted it was "getting tight" for him to be fit for the first Test.
Backup Options
Should Cummins not be fit, veteran batsman Smith will take over the captaincy.
All-rounder Cameron Green was withdrawn recently from Australia's squad for their one-day international series against the subcontinent side as a preventive step because of discomfort in his torso.
Bailey described it as a "minor" injury and mentioned that he'll feature in the state-level matches, so will be "well-prepared to be ready to bowl."
"Considerable effort has gone into creating the schedule for him to take part for the first Test as an batting and bowling option," Bailey explained.
"He was only going to play the starting games regardless. The way he swings the cricket bat in white-ball cricket, if it causes any delay for 24 more hours, the choice was made to adopt a safer strategy."
Match Calendar
The Ashes: Australia v England
Spanning from late 2025 to early 2026
