Australia paceman Peter Siddle is set for a "significant" spell on the sidelines due to a stress fracture in his back.
Siddle suffered the injury during the first Test against New Zealand in Wellington as he bowled just 20 overs for the match.
On his return to Australia, the 31-year-old underwent scans - and a lengthy stint out of cricket will follow for the Victorian.
"Peter returned to Melbourne on Monday and had scans following the bout of back pain he suffered during the first Test in Wellington," Cricket Australia physiotherapist David Beakley said.
"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.
"Whilst he is laid off with his current back injury, we will take the opportunity for Peter to have exploratory surgery on his left ankle to investigate and treat the cause of his ongoing ankle pain.
"Once that surgery is complete we will have a better idea of his prognosis and likely rehabilitation time frame."
Siddle was replaced by James Pattinson for the second Test, while in some good news for Australia, Mitchell Starc is targeting a July return from his foot injury.