Cummins out of final India Test, Smith to skipper Australia
Cummins left the tour ahead of the third Test and was initially expected to return, but with his mother in palliative care he has decided to stay in Australia.
"Pat Cummins has been ruled out of the fourth Test against India in Ahmedabad to remain in Australia with his family," Cricket Australia said in a brief statement.
"Steve Smith will captain Australia in the final Test of this series."
Under Cummins' leadership, Australia slumped to heavy defeats in the opening two Tests, but bounced back spectacularly when Smith took over to win the third Test by nine wickets.
The victory was only Australia's second Test win in India since 2004 and secured them a place in the ICC World Test Championship final in June at The Oval.
Despite revelling in being in charge again, Smith -- who was stripped of the captaincy and handed a year-long ban over a 2018 ball-tampering incident -- insisted after the third Test that his time as leader was "done".
The fourth and final Test starts in Ahmedabad on Thursday.
No decision has been made yet on whether Cummins will return to India for the three-match one-day international series that follows the Tests.
But fast bowler Jhye Richardson suffered a recurrence of a left hamstring injury over the weekend and has been ruled out of the limited-overs games, with Nathan Ellis replacing him in the squad.