Thursday 4 May 2017 14:49, UK
Dane Coles is the latest New Zealand player battling fitness issues ahead of the British and Irish Lions tour.
The Hurricanes hooker has not played since he injured his knee against the Highlanders on March 18, and he also strained a calf muscle in training.
But what should be a straightforward recovery has been complicated by exercise-induced headaches that are a typical sign of a player with concussion.
Hurricanes coach Chris Boyd said the condition was a mystery, as Coles did not suffer an obvious head injury in his last match.
"The source of it is completely unknown to us and that's made it a little bit more complex," said Boyd.
Coles must now pass concussion protocols before returning to play.
In the meantime, the headaches are preventing the 49-Test hooker from exercising enough to overcome his injuries, meaning he will struggle to be match-fit for the Lions.
Warren Gatland's side arrive in New Zealand in early June and their first Test against the All Blacks is June 24.
Other New Zealand players currently on the sick list are Kieran Read, Jerome Kaino, Ben Smith, Nehe Milner-Skudder, Patrick Tuipulotu, Elliot Dixon, Lima Sopoaga and Tawera Kerr-Barlow.
