Australian fast bowler Ryan Harris faces a lengthy spell on the sidelines following an operation on his troublesome right knee.
Harris was instrumental in Australia's 2-1 Test series win over South Africa, playing through the pain barrier to take the last two wickets to fall in the third Test in Cape Town.
He finished the second innings with figures of four for 32 as Australia wrapped up a 245-run win.
After returning to Australia, Harris underwent an operation to repair damage to his knee.
Cricket Australia physiotherapist Alex Kountouris confirmed: "Ryan underwent surgery yesterday on his right knee, which included a clean out of some loose bits of bone and removing bone spurs within the joint.
"Ryan will be on crutches for a few weeks and we expect a long rehabilitation period.
"Hopefully for Ryan he will be fit to play in the Test series against Pakistan later in the year but we will continue to assess his progress over the period," he added.
Harris has now taken 103 wickets in 24 Tests for Australia, helping them beat England 5-0 in the Ashes by taking 22 wickets and then taking a further 10 against South Africa.
He took 24 in the 2013 Ashes series in England but his efforts were in vain as England won 3-0.
Australia are scheduled to play Pakistan in October, giving Harris more than six months to return to full fitness and make himself available for selection.
© Cricket World 2014