Wellington - Rising star Ardie Savea on Thursday re-committed to the All Blacks, but only until 2018 to leave a question mark over his participation in the 2019 World Cup.
The 22-year-old flanker, brother of blockbusting New Zealand winger Julian Savea, made his Test debut against Wales last month and is already a fan favourite.
The two-year contract extension until the end of 2018 guarantees his availability for next year's British and Irish Lions tour, as well as keeping him at Super Rugby club, Wellington Hurricanes.
New Zealand Rugby has preferred recently to sign up their stars until the end of 2019 as the All Blacks prepare to defend the Rugby World Cup they won last year.
Players who have committed to the 2019 campaign in Japan include Ardie's brother Julian, Sonny Bill Williams, Aaron Smith, Dane Coles and Brodie Retallick.
Players on contract until 2017 or 2018 tend to be older veterans such as All Blacks captain Kieran Read, Wyatt Crockett and Jerome Kaino.
New Zealand Rugby's (NZR) statement did not say why Savea had only committed for two years, although he could probably command a much-improved contract if his profile keeps rising as expected.
"He's a strong-minded individual who dances to his own beat, is highly respected by his peers and has huge potential," NZR general manager Neil Sorensen said.
"We're all excited to see how he grows over the next few years."
Savea, who still only has two Test caps, indicated he was taking nothing for granted.
"I'm loving my rugby right now at all levels of the game and I'm excited about the future with both the Hurricanes and, if I'm good enough to be selected again, the All Blacks."