"Next year's a really congested year with Commonwealth Games and all the other international fixtures so we want to have a look at these players now and also building forward into the 2019 World Cup."
The focus on youth comes at the expense of 30 year old goal shoot Cathrine Tuivaiti, who shot at 95 per cent for the Central Pulse. However, her lower shooting volume combined with several other factors to exclude her from contention.
"There are some areas that are off-court that were of concern to us," explained Southby. "Over the last six months we've been keeping an eye on those things and we're looking forward to the future now."
While Tuivaiti's international future looks bleak, Langman's could be resurrected, depending on whether she decides to stay in Australia or return home.
"Laura has been in communication with Netball New Zealand and she's got a really tough decision to make," said Southby.
"At this point in time, Laura's not available for this year. If she comes back to New Zealand next year in time for a New Zealand franchise then obviously she puts herself back into selection contention."
Silver Ferns trialists: Monica Falkner, Bailey Mes, Tiana Metuarau, Te Paea Selby-Rickit, Maria Tutaia, Maia Wilson, Gina Crampton, Kayla Cullen, Shannon Francois, Wendy Frew, Claire Kersten, Erikana Pedersen, Grace Rasmussen, Samantha Sinclair, Whitney Souness, Elisapeta Toeava, Karin Burger, Temalisi Fakahokotau, Katrina Grant, Kelly Jury, Phoenix Karaka, Storm Purvis, Michaela Sokolich-Beatson, Zoe Walker, Jane Watson.