Seamer Finn hurt his left knee when, after bowling in middle practice at Richardson Park in Perth, he hit himself while batting in the nets.
All-rounder Moeen, meanwhile, has been troubled by soreness in his left side.
Both will have scans on Friday and are therefore no longer in contention for the two-day fixture against a Western Australia XI starting on Saturday at the WACA.
One man who will be in the thick of the action is Mark Stoneman, out to cement his position as Alastair Cook’s latest opening partner after making a largely favourable impression in three Tests against West Indies over the summer.
The 30-year-old said: “It’s one of the pinnacles of the sport to get on an Ashes tour. It’s massive – couldn’t be any bigger really.
“The first three Tests against West Indies were great. I don’t think I’ve ever had as much fun playing cricket.
“Obviously, the Ashes is just something completely different and totally new (for me) … the buzz around it and the build-up is on another level.”
The left-hander is delighted his belated promotion has coincided with the biggest series of all.
“The tour only comes round every four years, and to get the timing right to get my opportunity now is fantastic – and I want to make the most of it,” he said.
“It’s up there with the toughest challenges in the world, against the new ball in Australia, with the quick bowlers they’ve had through their history.
“It’ll be something, I hope, I can stand up to.”
Having fun, lads? 😀 pic.twitter.com/nojyc4pjax
— England Cricket (@englandcricket) November 1, 2017
Stoneman met his Australian wife Serene on one of his early winters down under to play Grade cricket in Sydney, and is confident he can count on her unqualified support despite the native allegiance.
“The wife is definitely backing me and England,” he said.
“The in-laws want to see me do well, (but) I’m sure they’ll be keen for Australia to do well too.”
He will be doing so with a sense of responsibility on and off the pitch.
Indirectly referencing the absence of Ben Stokes – left at home in England to discover whether he will be charged with causing actual bodily harm after a late-night altercation outside a Bristol nightclub – Stoneman spelled out his intentions.
“[I’ll have] a fantastic sense of pride, and hope we do justice to ourselves on the pitch and also as people off the field as well – conduct ourselves in a manner that everyone back home can be proud of,” he said.
“Obviously recent events have cast a bit of a shadow on that, but it’s up to us to … represent ourselves in a good fashion.”
In the middle, he knows from past experience there will be moments of provocation from England’s hosts – but he does not appear too worried.
“I think Aussies in general, if they get an Englishman in front of them, they’re keen to have a bit of a chirp,” he said.
“It should be good fun – I’m quite looking forward to it, see what the sledgers have got for us.”
Australia limited-overs seamer Nathan Coulter-Nile will captain a second-string WA XI against England this weekend.
In two further warm-up matches, in Adelaide and Townsville, England will face a crop of rising stars but only wicketkeeper Tim Paine and seamer Gurinder Sandhu with international experience in a 12-man Cricket Australia XI squad.
