With Alastair Cook, Ian Bell, James Anderson, Stuart Broad and Graeme Swann all rested after a successful Ashes campaign, Morgan will lead some unfamiliar faces into battle against the tourists.
Given the lack of experience in the England line-up, Morgan has urged 33-year-old Surrey batsman Pietersen to lead the way.
"Kev offers a hell of a lot as a senior player and as a batsman," Morgan told a press conference.
"As a senior player he leads by example with the confidence with which he goes about his business. People rub off on that and that's crucial.
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"In that regard, I think he's fantastic to have in the squad and back in for the one-day series."
Despite the absences of Bell and regular captain Cook, Morgan said that Pietersen was not guaranteed to open the batting against the Australians.
"It's certainly an option. Kev's opened the batting for England before and done well," he said.
"He also bats in the middle-order as a very explosive player. He's very versatile in that regard so we'll be looking at both options."
"Cooky and Belly have been very successful now for a couple of years and they've been a huge part of our success as a one-day team," said the Irishman.
"With the two new balls in one-day cricket it makes that role more difficult now, so it's an important role and one that we recognise needs filling."
Sussex bowler Chris Jordan could make his England debut tomorrow and Morgan says working alongside budding debutants has been the highlight of his role so far.
"Those games (as captain) in particular I've really enjoyed. The things I've most enjoyed about them has been handing out caps to debutants, he said.