The Rabbitohs half has been named to make his State of Origin debut next week, replacing the out-of-form James Maloney.
Maloney's Penrith halves partner Nathan Cleary's retained his jersey.
Fittler says Walker's been in the conversation for some time.
Walker's Rabbitohs teammate Cameron Murray, Canberra pair Nick Cotric and Jack Wighton and Brisbane's Payne Haas are the other debutants.
The Queensland squad is named later this morning.
RUGBY LEAGUE COVERAGE POWERED BY MACHINERY HOUSE - IN A LEAGUE OF THEIR OWN.
