"Alyssa will bring a lot of creativity to the Ferns - her skills on the ball are just different compared with what we have in the team so far," said Klimkova. "She's a very unpredictable player and it will be fun to see how she fits in, and how she adapts to the greater physicality and speed of senior international football."
Adjusting to the senior game will be a test, but there is no doubt the 18 year old is an exciting proposition with a unique skillset. Klimkova is prepared to be patient with Whinham.
"I don't want to put a lot of restrictions on her," said Klimkova. "I want her to enjoy as much as possible and learn from the older players, learn from the coaches."
Whinham is one of five Phoenix players in the squad, along with midfielder Betsy Hassett, winger Paige Satchell and defenders Kate Taylor and Mackenzie Barry.
Former captain Abby Erceg is absent once again, with Klimkova confirming she was unavailable.
"It is the same story," said Klimkova. "Abby is focusing on her club, fighting for the playoff spot and that is her priority."
Erceg has appeared in just two of the last 13 matches for the Ferns, mostly due to preferring to remain with her club. However, Klimkova said the door remains open for the 146-game veteran.
"After Japan I want to connect with her again and make a plan for the future," said Klimkova.
The Ferns (world No 22) will reassemble off the back of victories earlier this month over Mexico (1-0) and the Philippines (2-1), which broke a long winless streak.
However Mexico (No 37) missed qualifying for the 2023 World Cup, with United States, Costa Rica, Canada and Jamaica emerging from Concacaf, while the Philippines (No 53) are ranked below nine other Asian teams.
Japan (No 11) will be a different proposition, one of the most consistent teams in the world over the last decade.
They are undefeated since February, when they were eliminated on penalties by China in the semifinals of the AFC Women's Championship. Since then they have beaten Serbia, Finland, South Korea and Taiwan.
"We want to be a good competitor for Japan, we will be ready to surprise them with our counter and transition," said Klimkova.
Football Ferns squad
Goalkeepers: Vic Esson, Anna Leat, Erin Nayler.
Defenders: Liz Anton, Mackenzie Barry, CJ Bott, Claudia Bunge, Ally Green, Meikayla Moore, Ali Riley, Kate Taylor.
Midfielders: Hannah Blake, Katie Bowen, Olivia Chance, Betsy Hassett, Malia Steinmetz, Alyssa Whinham.
Forwards: Jacqui Hand, Grace Jale, Indiah Paige-Riley, Gabi Rennie, Emma Rolston, Paige Satchell, Hannah Wilkinson.