Sydney - Senior paceman Peter Siddle faces a lengthy period out of the game with a stress fracture in his back, Cricket Australia said on Thursday.
Siddle, 31, was forced out of this week's second Test against New Zealand in Christchurch after back trouble and was replaced by fellow Victorian quick James Pattinson.
"Peter returned to Melbourne on Monday and had scans following the bout of back pain he suffered during the first Test in Wellington," team physiotherapist David Beakley said in a statement.
"Unfortunately those scans have indicated a stress fracture in his lower back.
"He will now require a significant amount of time away from the game with a lengthy rehabilitation process."
Beakley said the time off cricket will enable Siddle to also have exploratory surgery on his left ankle.
"Once that surgery is complete we will have a better idea of his prognosis and likely rehabilitation time frame," he said.
Siddle's setback continues a run of injuries for Australia's pace battery, including spearhead Mitchell Starc, who had surgery on his right ankle last month.
Siddle has taken 208 wickets in 61 Tests at 29.88.