Ryan Harris has warned he may miss Australia's Test tour against Pakistan in October in favour of extending his rehabilitation from knee surgery to prolong his career.

Harris says his recovery from surgery on his right knee remains on track and the fast-bowler is keen for the tour of the United Arab Emirates but concedes there is a "reasonable chance" he will miss the tour.

"Playing against Pakistan is a goal, but I may struggle," said Harris. "There is a reasonable chance I won’t be able to get up for that.

"With the Australian team and the culture we have got, I don’t want to miss any games of Test cricket. But, unfortunately, there might be some games I might not be able to play because of my knee.

"I might have to start with the (Queensland) Bulls and work up from there," Harris told News Limited.

Should Harris not come up for the tour, it could open the door for Peter Siddle to force his way back into the side after the Victorian was dropped for the third Test against South Africa in Cape Town.

Harris has played Australia's past 12 Test matches, stretching back to Lord's last July. Injury had previously kept him to just 12 in the three years prior to that since his debut in March 2010.

The next Ashes series in the UK in mid-2015 remains the 34-year-old's No.1 goal but he hinted he may play on after that, with home series against New Zealand and West Indies due in 2015-16.

"My goal is to get to the Ashes next year but I will probably reassess if and when I get there," Harris said. "If we go well there and I am still going all right, a home series might be nice to finish on."

Siddle has taken up a stint with English county side Nottinghamshire during the winter. His replacement in Cape Town, James Pattinson, is spending the winter modifying his technique after pulling up sore from that Test.

An end-of-season update from Cricket Australia last month revealed the technical issue identified with Pattinson.

"Pattinson experienced some lower-back soreness at the completion of the third Test against South Africa," CA's statement said.

"As such, advice from CA medical staff is for Pattinson to take a cautious approach during the off-season that will include rehabilitation, strength, conditioning and technique modification."

Harris has already begun to think about life after playing , recently named as an assistant coach for the Australia A winter series against India A and South Africa A.

"When it was offered to me I jumped at it. I didn't think it (a coaching opportunity) would come up so soon," Harris told cricket.com.au earlier this month.

"When Darren (Lehmann) was at Queensland with the Heat he let me go away on a couple of trips as bowling coach, which gave me some experience. (But) I've still got a lot to learn."