Ashton Agar will miss at least some of Australia A's winter matches and could yet be in doubt for the start of the domestic summer after suffering a shoulder injury at pre-season training.

Agar suffered the injury while training with Western Australia and scans on Monday afternoon revealed some disruption to the same area of his right shoulder that was operated on last year.

"Ashton injured his right shoulder during a WACA pre-season training camp and scans have confirmed that he has disrupted some of the structures that were surgically repaired in April 2016," Alex Kountouris, Cricket Australia's sports science and sports medicine manager, said.

"He is due to see a specialist next week to determine if he will require surgery and when he is likely to return to training and playing. He will definitely miss the start of the quadrangular A series, but whether he takes any part in it and whether he will be fit for the Matador BBQs One-Day Cup will be determined in due course."

Agar played two Tests on the 2013 Ashes tour of England, made his one-day international debut in England last year, and was part of Australia's team at the World T20 in India earlier this year. He was named in the Australia A squad for their winter matches, which include four four-day games against South Africa A and India A, and a quadrangular one-day series.