The pair have replaced Camilla Lees and Jodi Brown, who will make a return to the team for the New Zealand leg of the series with test matches in Wellington, Tauranga and Hamilton.
Coach Wai Taumaunu said the quad series, that also involves Australia, England and South Africa, provided a great opportunity to further develop depth within the squad.
"It's a great opportunity for both Anna and Grace to stamp their marks in the side, and for Jodi and Camilla to build on their performances in the Constellation Cup," said Taumaunu.
The Silver Ferns will play South Africa in Adelaide in their first match in the series on October 14 before tackling England three days later in Newcastle and meeting Australia in Sydney on October 21.
One of Taumaunu's goals during this busy international calendar has been to maximise the opportunities for the full squad of 15 and the coach believes she can do that by targeting the series in two stages - the three tests in Australia and three in New Zealand.
"We are mindful that this is a busy international season for players and that we want to develop depth within the squad," she said.
Silver Ferns' squad for the Australian leg
Shooters: Irene van Dyk, Maria Tutaia, Cathrine Latu, Anna Thompson, Midcourt: Laura Langman (vice-captain), Grace Rasmussen, Bailey Mes, Kayla Cullen, Defence: Leana de Bruin, Katrina Grant, Anna Harrison, Casey Williams (captain).
New Zealand leg
Shooters: Irene van Dyk, Maria Tutaia, Cathrine Latu, Jodi Brown, Midcourt: Laura Langman (vice-captain), Camilla Lees, Bailey Mes, Kayla Cullen, Defence: Leana de Bruin, Katrina Grant, Anna Harrison, Casey Williams (captain).
