David Pocock sat out Wallabies' training in London on Monday and remains in doubt for this weekend's clash with England after having scans on a calf muscle.
Pocock hasn't played since suffering a knee injury in the opening Bledisloe Cup game against the All Blacks in August.
He attended training on Monday afternoon but was only a spectator along with fullback Mike Harris, who has a minor leg injury.
Pocock was expected to make his long-awaited return from injury at Twickenham on Saturday (Sunday NZ time) but this latest setback has the No.7 in serious doubt.
Robbie Deans' side has never needed Pocock more after they were trounced 33-6 in their European tour opener against France.
With Harris staying under cover, Berrick Barnes ran at fullback as the backline worked on some set moves.
Barnes, who made his return off the bench against France, is expected to start against England.
The tour has the potential to turn into a nightmare for the Wallabies facing a confident England side who are chasing a third straight Cook Cup win over Australia after running in seven tries to destroy Fiji 54-12 at the weekend.