Seamer Atkinson Adds to the English team's Fitness Concerns.
'Significant concern' for England as Atkinson is forced off due to a hamstring issue.
The English seamer increased the injury concerns plaguing England when he left the playing area during Saturday's play of the Boxing Day Test versus the Australians.
The right-arm seamer pulled up with his hamstring post-delivery in his spell on Saturday.
The touring camp indicated the 27-year-old felt some "soreness" and required time off the field to undergo evaluation "in the coming hours".
The final Test of the series at the SCG gets underway at the end of the week.
England have already lost key quicks one seamer due to knee trouble and Jofra Archer to a side strain on the current trip.
Matthew Fisher was brought into the squad to provide backup.
The seamer had a tough time in the opening two Tests, taking just a handful of scalps.
He was omitted from the previous Test, before being recalled for the Boxing Day match as Archer's replacement.
The county bowler performed better in the fourth Test, claiming a couple of wickets during the host's first knock, and scoring 28 runs with the bat as one of just three England players who passed ten runs.
Following a brief spell in Australia's second innings, he came back for the second day's play and removed Scott Boland taken by the wicketkeeper.
However, on the final ball of his spell, he sent down a change of pace to Travis Head and suddenly grabbed his left hamstring.
Atkinson was brought back for the fourth Ashes Test following his omission the Adelaide game.
