Sarfraz Ahmed has become the second Pakistan player forced to return home this week in a troubled lead-up to Friday's opening one-day international against Australia in Brisbane.
Captain Azhar Ali confirmed on Thursday that his team will be without their vice-captain and wicketkeeper for the opening game at the Gabba and possibly this month's entire five-match series.
Azhar said Sarfraz had gone back to Pakistan to be with his mother, who is in intensive care in hospital.
Mohammad Rizwan will take the gloves for the first day-night match and could remain in the side if Sarfraz does not return to Australia.
The news comes just days after fast bowler Mohammad Irfan also left the team following the death of his mother.
"We'll definitely miss Sarfraz tomorrow. Hopefully, he can rejoin the team but, as for right now, he's not here," Azhar told reporters.
Pakistan have retained half the players who were involved in 3-0 Test series wipeout to Australia for the ODI part of their tour.
Azhar said the addition of some new faces and Tuesday's 196-run thumping of a Cricket Australia XI in a one-day practice game in Brisbane had helped lift the team's mood.
"I know it wasn't a very competitive game, but I still believe the batsmen who scored runs will get a lot of confidence," he said.
"The bowlers had a good outing as well. There's nothing like playing matches. It's good to be out there no matter what sort of team you play against."
Pakistan's need for victories is even more urgent given they are currently the eighth-ranked one-day nation in the world, three rankings points ahead of the West Indies.
If they drop out of the top eight by September, they'll miss out on automatic qualification for the 2019 World Cup and be forced to enter a 10-team qualifying tournament in Bangladesh in 2018.
Australia can extend their lead in the ODI rankings if they can pull off a series whitewash.
Australia lead Pakistan 33-16 head-to-head in Australia, including 15 wins in 19 ODIs this decade.