Usman Khawaja and Marcus Stoinis have returned - at least loosely - to the national team fold after being named in a 26-man preliminary squad for Australia's proposed white-ball tour of England in September.

Test batsman Travis Head has also been named in a white-ball squad for the first time since he missed selection for the 2019 World Cup, while Riley Meredith, Josh Philippe and Daniel Sams make their first appearances in a senior training group, likely to be seconded to the National Cricket Centre in Brisbane next month before a cut-down group is conveyed to the UK.

Khawaja and Stoinis were the two most high-profile names to lose their national contracts after falling out of favour last summer, though it had been made clear in Khawaja's case at least that he remained a likely top-order replacement in the event of injuries to the likes of David Warner, Steven Smith or the limited-overs captain Aaron Finch.

The selection chairman Trevor Hohns outlined the fact that a larger than usual squad would need to be sent should the tour go ahead, given the fact it will not be possible to send replacement players in the event of injury or illness. England are currently playing the West Indies in a biosecure "bubble" in the time of Covid-19 and similar arrangements are being worked through for an Australian tour.

"This preliminary list covers the contingencies of playing one-day internationals and T20 internationals in bio-secure hubs with the likely prospect of not being able to bring in replacements should the tour proceed," Hohns said.

"The preliminary list includes several exciting young players who have recently excelled at state level and in the BBL. These emerging players are among those we would like to develop further as we believe they have a bright future in Australian cricket. The preliminary list also has a view towards the upcoming T20 World Cup and in the longer term the 2023 World Cup."

Ben Oliver, Cricket Australia's head of national teams, said that negotiations with the ECB and the Australian and British governments were continuing with any potential quarantine requirements for the players on return to Australia, which currently has closed international borders, a key issue.

"There's a lot of complexity around the tour and international cricket at the moment, but we're doing everything we can to make sure we give that tour the best chance possible to proceed," he said. "We take the quarantining environment very seriously and it's important that we understand that fully before a decision on the tour is made.

"Obviously for elite cricketers, elite athletes generally, the ability to train and stay fit and keep ticking over is an important factor. The health and safety of players and staff and the public health component is most critical. The quarantine arrangements aren't confirmed. They obviously exist in terms of general international travel at the moment so that's something we're working through.

"'[It's] at the start of our home summer so we are interested to understand how we navigate that. Equally we are fully supportive of the quarantine requirements that are in place across Federal and State and Territory Governments and our obligations around that from a public health perspective. We're having constructive conversations with government agencies and particularly the ECB."

Oliver also confirmed that Hohns would continue as selection chairman for the forthcoming summer, after his previous contract ended earlier this year. "We're moving forward with our selection panel as it was at the end of last season," he said. "The panel is really focused on the challenges of the upcoming 12 months. We have some interesting challenges as we swap between formats and different tours that players are going to be involved in. Trevor is committed through this season."

In addition to the UK tour, originally slated for July, CA has also postponed a Test tour of Bangladesh and a limited-overs visit by Zimbabwe. Neither of the latter two series have as yet been rescheduled.