The pace bowler has secured 309 Test scalps in 71 Test matches with an stellar bowling average.
The Australian chief selector the selector has confirmed that skipper Cummins will have a crucial role in the forthcoming Ashes series.
Rumors had circulated that the veteran bowler might be unavailable due to a stress fracture in his back that had not yet healed.
Earlier indications from the squad suggested no official announcement had been made regarding Cummins' participation, with the Test matches set to start on 21 November in Perth.
Bailey expressed that the captain is progressing and was "optimistic" about his chances of participating.
"It's clear that the window is narrowing and there are permutations around that, not just his injury, but further aspects," Bailey remarked.
"It's positive. There's strong faith that he's going to play a major part. With luck it's the first Test. If not, we'll adjust."
Cummins was ruled out the white-ball matches against New Zealand and India recently after examinations confirmed a stress reaction in his back.
There is a track record of back injuries, with flare-ups in several earlier campaigns forcing him out of several home seasons in four years.
He emphasized he would be ""aggressive" and "take risks" in his recovery plan to secure his spot for the series.
He mentioned that there was no confirmation if he had started his bowling workouts as part of his comeback but acknowledged it was "getting tight" for him to be fit for the initial match.
If he's unavailable, veteran batsman Smith will take over the captaincy.
All-rounder Cameron Green was recently pulled out from Australia's squad for their one-day international series against the subcontinent side as a precautionary measure because of soreness in his side.
The selector characterized it as a "minor" injury and stated that he's scheduled to appear in the domestic first-class competition, so will be "in a good place to be ready to bowl."
"Considerable effort has gone into creating the schedule for him to be available for the first Test as an dual-role player," he elaborated.
"He was only going to play the initial matches in any case. The way he swings the bat in limited-overs, should it hinder progress for a short period, we opted to adopt a safer strategy."
Australia vs England: The Ashes
Spanning from late 2025 to early 2026