Australia will be forced to enter Wednesday's World Cup clash with Pakistan without a pace-bowling allrounder, after Marcus Stoinis was ruled out with a side strain.
Without another allrounder in their squad that bowls at speed, Stoinis is out of the tournament indefinitely with Mitch Marsh flying to England early as a precaution.
Stoinis' absence will place extra importance on the flexibility of Australia's side in Taunton.
Australia will either pick a fifth bowler and bump Alex Carey up to No.6 in a shortened batting order, or play Shaun Marsh and rely on Glenn Maxwell and Steve Smith to get through a combined 10 overs.
Rain is also forecast for the majority of the day, although there is some chance of it clearing to allow for the possibility of a shortened game.
"You just have to make sure you're as well prepared as you can be," Finch said of the weather.
"You never bank on rain or anything like that. You always prepare for the full 50-overs and then you work on the spot.
"Your team might change if it's a really delayed start or something like that.
"Everyone just has to be prepared to shuffle their roles around.
"And be really adaptable and that's one thing we've been really, really clear with the players that we want everyone to be adaptable and be ready to go at any situation."
Rain looks set to be a continued threat in this year's tournament.
Three matches have already been washed out, the latest being Sri Lanka's match against Bangladesh on Tuesday.
If Pakistan and Australia fail to achieve an outcome on Wednesday, it will be Pakistan's second straight no result - all but cancelling out the upset win they claimed over England last week.
Further rain is expected for the rest of the week, potentially affecting India's heavyweight clash with New Zealand in Nottingham.
It comes after Australia had a wretched run through the 2017 Champions Trophy in England, after the Aussies had two of their three group games washed out and lost the other on the Duckworth-Lewis-Stern method.
"(Weather) might play a huge part in the next few days," Finch said. I think.
"It's important that you get early wins on the board because if they do play a part you don't want to be on the wrong end of a couple of washouts."