Fast bowler Atkinson Adds to England's Fitness Concerns.
'Major setback' for the English camp after Atkinson goes off suffering a hamstring problem.
The English seamer added to England's injury problems when he left the field on the second morning of the Boxing Day Test versus the Australians.
The pace bowler experienced discomfort in his left leg after the final ball of the fourth over at the MCG.
The England team reported the 27-year-old felt some "soreness" and required time on the sidelines to undergo evaluation "in the coming hours".
The series decider in this Ashes battle beginning on 4 January gets underway at the end of the week.
The English side has been without key quicks one seamer due to knee trouble and another paceman because of a side injury on the current trip.
Matthew Fisher was brought into the squad to provide backup.
Atkinson struggled in the opening two Tests, taking just a handful of scalps.
He was omitted from the previous Test, only to be brought back for the Melbourne Test as Archer's replacement.
The county bowler improved at the MCG, bagging two scalps with the ball, then making 28 with the bat among just a trio of England players to reach double figures.
Post a single over late on the first day, he resumed on Saturday morning and had nightwatchman Scott Boland caught behind.
Unfortunately, at the end of his spell, he delivered a variation to the batsman and promptly felt at his leg.
Gus Atkinson was recalled for the Melbourne match having missed of the third.
