'Significant concern' for England as Atkinson goes off suffering a hamstring problem.
Gus Atkinson further complicated the injury concerns plaguing England after leaving the ground on the second morning of the Boxing Day Test versus the Australians.
The right-arm seamer pulled up with his left leg post-delivery in his spell during the morning session.
Team management indicated Atkinson reported "discomfort" and was to take time on the sidelines for further assessment "over the next few hours".
The concluding match in this Ashes battle beginning on 4 January starts on Sunday, 4 January.
The visitors have previously lost strike bowlers Mark Wood due to knee trouble and another paceman to a side strain on the current trip.
Matthew Fisher was brought into the squad as cover for Wood.
Atkinson struggled in the opening two Tests, taking just a handful of scalps.
He was left out from the previous Test, before being recalled for the fourth Test as Archer's replacement.
Surrey's Atkinson showed better form in Melbourne, claiming a couple of wickets in Australia's first innings, then making 28 while batting as one of just three English batsmen who passed ten runs.
Post a single over late on the first day, he returned for the second day's play and removed Scott Boland taken by the wicketkeeper.
Yet, towards the conclusion of his spell, he delivered a variation to the batsman and suddenly grabbed at his leg.
Gus Atkinson was brought back for the Melbourne match following his omission the Adelaide game.