Fast bowler Gus Atkinson Compounds England's Fitness Concerns.
'Serious blow' for the English camp after Atkinson leaves the field suffering a hamstring problem.
The English seamer added to England's injury problems after leaving the field during Saturday's play of the Boxing Day Test in the Ashes series.
Atkinson experienced discomfort in his left hamstring immediately following a delivery that he bowled on Saturday.
The touring camp reported Atkinson felt some "soreness" and was to take time off the field for further assessment "over the next few hours".
The series decider in this Ashes battle at the SCG begins on Sunday, 4 January.
The visitors have already lost fast bowlers Mark Wood with a knee problem and another paceman with an abdominal strain on this Ashes tour.
A replacement bowler was brought into the squad to provide backup.
The seamer had a tough time in the opening two Tests, managing only three wickets.
He was left out from the previous Test, then recalled for the Melbourne Test in the playing XI.
The county bowler showed better form in Melbourne, bagging two scalps in Australia's first innings, and scoring 28 runs while batting among just a trio of English batsmen to get into double digits.
Post a single over in Australia's second innings, he returned the next day and had nightwatchman edging to the keeper.
Unfortunately, towards the conclusion of that over, he sent down a change of pace to the batsman and suddenly grabbed at his leg.
The English bowler was brought back for the Boxing Day Test having missed the previous Test.
