Australia captain Pat Cummins says it is "less likely than likely" that he will be fit for the Ashes series opener against England next month.
The fast bowler is recovering from lumbar bone stress in his lower back and has not played since July, although he has resumed running in training.
The 32-year-old faces a race to be fit for the first Test in Perth on November 21, but admits he may be prepared to gamble with his fitness given the significance of the series.
Cummins, who said he planned to resume bowling drills next week, told Cricket Australia's official website: "You'd want at least probably a month in the nets.
"If you play a Test match, you want to make sure you're right to bowl 20 overs in a day and you don't have to really think about it.
"So four weeks is pretty tight, bu