Aggressive fast bowler Pattinson and line-and-length specialist Siddle have been nursing injuries since February.

The uncertain short-term future of Nathan Coulter-Nile, who returned last week from Sri Lanka because of a back stress fracture, and the inability of Pat Cummins to consistently take to the field means Australia cannot afford to have new-ball partners Mitchell Starc and Josh Hazlewood and back-up quick Jackson Bird hurt ahead of the home campaigns against South Africa and Pakistan.

The first Test against the Proteas in Perth begins on November 3, with players given only the one chance to impress in the Sheffield Shield, with that campaign starting on October 25.

Pattinson, 26, claimed six wickets in the second Test in New Zealand in February but finished the match complaining of shin soreness. Scans later confirmed he had a "bone stress injury". His frustration was exacerbated when it emerged scans had also revealed a recurrence of stress fractures in his back.

Pattinson, who has taken 70 wickets at 26.15 in 17 Tests, had remodelled his action for last summer, having battled long-term back issues.

Victorian chairman of selectors Andrew Lynch said a return date for Pattinson was still unclear. Lynch all but confirmed Pattinson would not feature in the domestic Matador one-day series, with the Bushrangers' campaign starting against South Australia in Perth on October 5.

"James has been consistent with his training output over winter. He's working hard to have his body in the physical shape required to sustain the demands of bowling when the time comes," Lynch said.

"We don't have a definitive date for his return yet, but his strong progress to date is promising heading into summer."

Pattinson made his Test debut in December 2011, claiming a five-wicket haul against New Zealand, but has since been hampered by injury. He returned from almost a two-year absence because of back stress fractures in the three-Test series against the West Indies last summer, claiming 13 wickets at 22.46.

Siddle, who turns 32 in November, has also dealt with back stress fractures and was forced to the sidelines after the first Test in New Zealand.

"It's great to see Peter back in the nets on a specific recovery plan to ensure he gets the best out of his sessions," Lynch said.

The 61-Test veteran also underwent exploratory surgery on his left ankle, having earlier missed the third Test against the West Indies because of an ankle issue.

"He's been back bowling with a modified run up for four to six weeks now, and his rehabilitation from his ankle injury is progressing well. We look forward to his return later in the year," Lynch said.

Siddle will join his Victorian teammates on a pre-season trip to Mooloolaba on Queensland's Sunshine Coast this week and is hopeful of playing some part in the Matador Cup.

Cummins, who has battled back stress problems, returned to action last week in a six-over spell for NSW in a trial game against Queensland on the Sunshine Coast.

As an 18-year-old in 2011, Cummins claimed seven wickets and led Australia to victory over South Africa in Johannesburg on debut, but he has not played another Test. He has since taken part in only eight first-class matches, although he has represented Australia in 18 one-day internationals and 15 Twenty20 matches.

The Blues hope he will be fit for the domestic one-day opener against a Cricket Australia XI on October 7.