All Blacks lock Patrick Tuipulotu has been suspended after testing positive for a banned substance - but was shocked by the drug test result, New Zealand Rugby says.
Tuipulotu missed the All Blacks' final game against France in November after returning home from the European tour early due to what was described as personal reasons.
Since then he has also been sidelined from the Blues Super Rugby franchise's pre-season training, again due to ongoing personal issues.
Following media reports, New Zealand Rugby and the Rugby Players Association on Sunday confirmed they had been notified in November last year the 23-year-old had tested positive for a banned drug.
"(We) notified that a doping control sample provided by Patrick Tuipulotu had, reportedly, revealed the presence of a specified substance listed on the World Anti-Doping Agency's 2016 Prohibited List," they said in a joint statement.
"NZR and NZRPA can confirm that Patrick was shocked by the test result and is working hard to identify the source of the specified substance."
It said Tuipulotu "remains provisionally suspended pending resolution of this matter", in accordance with anti-doping rules.
The organisations said due to strict confidentiality obligations they could make no further comments.
Comment has also been sought from Tuipulotu's agent, Ben Boyle and the Blues.