The main contenders for the position are Temalisi Fakahokotau - the Mystics' break-out star last season - and Kayla Cullen, who is fighting her way back from a knee injury, but Silver Ferns coach Waimarama Taumaunu said she has also been impressed with the form of the Steel's Phoenix Karaka and Magic youngster Jamie-Lee Price this week.
"That [defensive spot] is actually going to be quite a tough call, there is a lot of competition in there," said Taumaunu.
Cullen lined up at this week's trials with only two weeks of court work following several major setbacks in her rehabilitation from a knee reconstruction last year.
When at her best, Cullen brings stunning athleticism and an x-factor to the team. But the Constellation Cup, which starts in Invercargill in two weeks' time, will likely be too early for Cullen, with the two tests against England late next month a more realistic proposition.
"I'm still not that confident doing certain things on court but I guess the more I play the more confident I will become. It is really hard coming back from an injury like that and going straight back into playing at this level," the 22-year-old said.
"I think the challenge for me is mostly a mental one."
Team management have decided the best way for the youngster to get over that mental hurdle is to throw her straight into the deep end this week. "I'm not wrapping her in cotton wool - we need to see what she can do," said Taumaunu.