GREENS MP Colleen Hartland will retire early when Parliament resumes next month.
Ms Hartland unexpectedly announced in June that she would not run for re-election in November, although it was expected she would see out her term.
The Greens will slot public servant Huong Truong into her Western Metropolitan Region upper house seat.
Retirements in the Legislative Council do no trigger by-elections.
"It's been an incredible honour to represent my community in the Victorian Parliament, but it's a relentless job that causes exhaustion and this does have an impact on your health," Ms Hartland said.
"I have decided to retire from the parliament before this begins to have a major impact on me.
"It is time for me to hand over the baton."
It is the second time this term a longstanding Greens MP has retired early, following the departure of former leader Greg Barber.
With replacements able to be sent straight into parliament, the move has raised questions over whether the Greens are attempting to give the new MPs a head start on election in November's vote.
Ms Truong, from Sunshine, has worked in the public service for more than a decade in areas including transport, environment and welfare.
She unsuccessfully ran as a Greens candidate in the federal seat of Gorton in 2007.
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