Australia's Ryan Harris out for six months after knee surgery

Australia fast bowler Ryan Harris is expected to be out for six months following a knee operation.

Harris, 34, played a key role in Australia's recent series win in South Africa and the 5-0 Ashes victory over England.

"Ryan will be on crutches for a few weeks and we expect a long rehabilitation period," said Australia physiotherapist Alex Kountouris.

"Hopefully he will be fit to play against Pakistan [in October]."

Harris has struggled with injury throughout his career and had never played four Tests in a row until the 2013 Ashes in England.

However, the final Test against South Africa last week - in which he claimed seven wickets to seal a series win - was his 12th in succession.

He has taken 103 wickets  at an average of 22.56 in 24 Tests.

Australia play two Tests against Pakistan in October, likely to take place in the United Arab Emirates, followed by a four-Test series at home to India later in the year.