All Black wing Rieko Ioane could miss at Saturday’s Test against France after it was revealed that he has mumps.
This is not the first time mumps have crept into the World Champions camp.
Just before their departure from New Zealand, Crusaders midfielder Jack Goodhue also came down with the disease which forced him to delay his departure and miss the chance to make his first appearance for the All Blacks, against the Barbarians at Twickenham on Saturday.
Hansen, however, revealed that the two incidents were unrelated. He emphasised that the right steps have been taken to ensure there is no spread of the virus through the All Blacks camp.
"The doc has done a great job, and we've isolated him [Ioane], so we're not worried about it spreading," Hansen told stuff.co.nz.
"It's unrelated to Jack Goodhue's because they haven't been in contact, but it has obviously come out of Auckland somewhere,"
The 20-year-old Ioane, who scored eight tries in his eight Test appearances this year, has become an integral part of Hansen's squad and if he misses the French Test it would be a major blow.
Furthermore, with Ben Smith, Nehe Milner-Skudder and Israel Dagg all unavailable and a big question mark hanging over Julian Savea's head, Hansen has limited option.
"It will be touch and go through if he is available [to face France]. He trained this morning, so we'll just have to see how well he comes through the week.
"Nonetheless, it's not too bad,", the coach added.
Aside from Ioane, New Zealand will also monitor Jerome Kaino’s knee injury ahead of the All Blacks’ clash against France.
Kaino suffered knee sprain during Saturday’s 31-22 victory over the Barbarians at Twickenham.