The full-back was replaced 15 minutes from time in the Wallabies' 33-13 demolition of England at Twickenham on Saturday, which sealed their place in the quarter-finals and knocked the hosts out.
Burgess dumped from England squad Hooper handed World Cup ban
Folau faces a battle to prove his fitness ahead of the clash with Warren Gatland's side back at Twickenham, while wing Rob Horne is set to miss out due to a shoulder injury, although that issue is not as serious as first feared.
"We have an injury concern over Israel," backs coach Stephen Larkham revealed.
"He came off the field in the game against England with a sore ankle and did not train yesterday [Monday]. We will see how he pulls up today and I am not sure if he will even train.
"Rob is still on the injured list but we are hopeful he can be turned around in a week or so.
"It is unlikely he will face Wales."
Flanker Michael Hooper will miss the Wales clash after he was handed a one-match ban for his illegal cleanout on England ful-back Mike Brown.