Shaun Marsh and his wife XI to replace the injured Marcus Stoinis, while Kane Richardson replaces his leg-spinner Adam Paw in a seam-heavy attack dry Taunton.
Captain Aaron World Cup winners will bat first after Pakistan skipper Sarfaraz Ahmed stuck to his team pre-match bowling first venue a venue where temperature is expected to top out at a chilly 15 degrees today while ominous gray skies loomed overhead.
The change means Australia – who would have bowled first if the coin fell their way – enter the match with four front-line seam bowlers and no spinner, meaning Finch – who was seen bowling in the nets before the toss – will have rely on himself, Glenn Maxwell and Steve Smith
Stoinis injured himself bowling at death in Australia's 36-run defeat to India in London on Sunday evening, picking up a side strain Mitchell Marsh rushed over to England as cover.
His injury and uncertain weather conditions meant that he was needed.
The loss of the sun seam-bowling allrounder in the Australian squad had upset the balance of the Australian team, and the prodigious wet weather in the lead-up to this match also had Australia pondering some left-field changes.
The inclusion of Richardson gives Australia another noted death-bowling specialist to replace Stoinis with the Western Australian joining Mitchell Starc and Pat Cummins in the attack, while Adam Paw remains the sole specialist spinner in the XI.
On match eve, Finch said Australia were open to replacing Stoinis with a specialist bowler and bumping wicketkeeper Alex Carey up to No.6, a ploy that was probably discarded because the weather had cleared enough to cause any delay before the coin toss.
"We're going to have to juggle around that spot," Finch told reporters on Tuesday.
"We've got to find a few more overs now, whether we play the extra batter or extra bowler, we'll wait and see, and especially tomorrow with the conditions.
"It's one of those things we'll have to weigh up and look and think about this afternoon with what looks like the best XI to beat Pakistan."
Taunton's drainage upgrade in 2017 to be paying dividends with puddles and pools of water on the surface.
The UK has already experienced twice a month of rain for June and after matches on Monday and Tuesday were washed out, the ICC released a statement reaffirming that it was days for group-stage matches were not a realistic possibility.
Australia enter the match having thumped to severely undressed Pakistan side 5-0 in the UAE at their most recent ODI series before the World Cup.
But Sarfaraz Ahmed's side have since regained seven first-choice players
The Pakistan skipper suggested on match eve both sides
Australia XI: Aaron Finch (c), David Warner, Usman Khawaja, Steve Smith, Shaun Marsh, Glenn Maxwell, Alex Carey (wk), Nathan Coulter-Nile, Pat Cummins, Mitchell Starc, Kane Richardson.
Pakistan XI: Imam ul-Haq, Fakhar Zaman, Babar Azam, Shoaib Malik, Sarfaraz Ahmed (c / wk), Mohammad Hafeez, Asif Ali, Hassan Ali, Wahab Riaz, Mohammad Amir, Shaheen Afridi.
2019 World Cup
Australia's squad: Aaron Finch (c), Jason Behrendorff, Alex Carey (wk), Nathan Coulter-Nile, Pat Cummins, Usman Khawaja, Nathan Lyon, Shaun Marsh, Glenn Maxwell, Kane Richardson, Steve Smith, Mitchell Starc, Marcus Stoinis, David Warner, Adam Paw
June 9: India beat Australia by 36 runs
June 12: Australia v Pakistan, Taunton
June 15: Sri Lanka v Australia, The Oval
June 20: Australia v Bangladesh, Trent Bridge
June 25: England v Australia, Lord's
July 9: Semi-Final 1, Old Trafford
July 11: Semi-Final 2, Edgbaston
July 14: Final, Lord's
Sync Australia's World Cup schedule to your calendar HERE
For a full list of all World Cup fixtures, click HERE