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Dropped after the first Test in Adelaide in India, the 30-year-old now faces the prospect of slipping below the younger members of the pace attack in the pecking order.
But Siddle, a veteran of 56 Tests, says he is young enough to reclaim his place in the Test team.
"You look at Ryan Harris and he is 35 and he is still going so there is still plenty of time," Siddle said.
"I have been able to stay fit and on the park for the past three years now, that is a bonus, the body is feeling good.
"I've been good mates with Ryan for the past 10 or so years, and watched him go from being a rival coming through to a good player for South Australia and now a teammate in the Australia side.
"He has relished his opportunities and changed his game from when he turned 30.
"That has shown me that once you cross over to the age of 30, there is still lots of cricket to be played and lots of opportunity and things can happen."
With no Sheffield Shield cricket played until the middle of February, Siddle is spending the summer playing for Melbourne Renegades, with the potential for some Victorian Premier Cricket to be squeezed in before the Bushrangers resume the four-day season.
Making the World Cup squad seems farfetched when you consider he has not played an ODI since 2010.
Hazlewood and Starc are his immediate successors, while selectors also have their eyes on Sean Abbott from New South Wales and Western Australian left-armer Jason Behrendorff.
Australia's next Test series is in June 2015 against the West Indies. By then rehabilitating trio James Pattinson, Pat Cummins and Jackson Bird are slated to be fit and firing.
Can 30-year-old Peter Siddle emulate Ryan Harris?
