Marsh missed the first ODI in Perth on Sunday after requiring an operation to remove an abscess from his buttock.
D’Arcy Short replaced Marsh at No.3 but fell for a second-ball duck as Australia were bundled out for just 152.
Australia’s chairman of selectors Trevor Hohns said McDermott’s inclusion was to give Australia more batting options if Marsh is unable to play on Friday.
“Part of the decision to include Ben is to ensure we have appropriate coverage should Shaun Marsh fail to recover in time for Friday’s second ODI,” Hohns said. “We will continue to monitor Shaun’s progress and give him every opportunity to prove his fitness ahead of the match.”
McDermott, 23, made his international debut last month in the UAE playing all four T20Is against the UAE and Pakistan. He was run out in all three of the matches against Pakistan.
McDermott was the second leading run-scorer in last month’s JLT Cup behind Chris Lynn, piling up 427 runs at an average of 71.16 and striking at 90.27. He made two centuries and two half-centuries in seven matches for Tasmania opening the batting.
His inclusion comes as Australia continue to search for the right mix with its batting line up in ODI cricket, with Aaron Finch, Travis Head, Alex Carey, Marsh, Short, Lynn, McDermott all best suited to batting in the first three spots in the order.