Finn jarred his left knee while batting in the nets on Thursday at training.
He crouched to the ground in pain after suffering the jar, and limped off gingerly to the change rooms.
Ali has a sore left side that has bothered him in recent days.
The duo will undergo scans on Friday in Perth, with their spots in doubt for this weekend's two-day tour match against a WA XI outfit at the WACA Ground.
