Brenden Aaronson says Christian Pulisic will "give his all" to be fit for the United States' second World Cup match against Australia after a calf injury.

Pulisic sustained the injury last week and reportedly further aggravated it in the USA's 4-1 win over Paraguay in their opening match in Group D.

He got an assist for Folarin Balogun's first goal before subsequently being taken off at half-time, with the USA already 3-0 up.

Pulisic now has four career goal contributions in the World Cup (one goal, three assists), tied with Clint Dempsey for second-most among USA players since 1966 (Landon Donovan sits top of that list with five).

The 27-year-old trained separately from the rest of the team on Wednesday, with the USA keeping him on a modified training schedule as they aim to get him on the pitch in Seattle on Friday.

"We're really hoping Christian is going to be back for the game, of course," ​Aaronson, who would be a potential replacement for Pulisic in the starting line-up, told reporters.

"I don't really know what is going ⁠on in particular, but we know that he is going to give us his all to get back ​into the team and be there for the game."

Australia proved a force to be reckoned with against Turkiye, facing 30 shots without conceding as they clinched a 2-0 victory.

Pulisic was very influential against Paraguay, forcing the own goal that opened the scoring, but Antonee Robinson is confident that even if they are without the forward, they have what it takes to get a good result against Australia.

"He has not been training fully with the group yet, but we've got a couple ​of days to see where he's at," Antonee Robinson said.

"Thankfully, we've got a lot of boys on the bench ​who are eager and ready to get involved in helping the team and a lot of quality.

"It's a long tournament. ‌If ⁠we don't have him back for the game, we're going to make sure we have him back for the rest of the way because we're going to need him."