Alexander is gutted having to leave the field with a knee injury
Australia suffered a double injury blow in a 49-3 win over Fiji a week before their first Test against England.
Utility back Adam Ashley-Cooper injured his ankle after a heavy tackle, while prop Ben Alexander was carried off when his leg got trapped during a ruck.
Alexander has suspected knee ligament damage and both players are doubts for the visit of Martin Johnson's side.
England play the Australian Barbarians in Perth on 8 June before the first of two Tests against the Wallabies.
Johnson's squad departed for their five-match tour down under on 31 May.
Both injuries will be a concern for Australia coach Robbie Deans, as well as a rather lacklustre first-half performance against the Fijians on Saturday.
Astute passing by fly-half Quade Cooper helped to create four tries and he scored one himself at Canberra Stadium as his team scored 35 unanswered points in the second half.
"I think we were able to turn it on after half-time and keep it on after that," Wallabies captain Rocky Elsom said.
"One thing you know about Fiji is that they're extremely difficult to tackle if you give them space, so I think we worked well as a [defensive] line there and the scoreline shows that."