New Zealand half-back Piri Weepu has been ruled out for around a month after it was determined he had recently suffered a minor stroke.
The 30-year-old - who has made 71 appearances for the All Blacks, playing a part in their World Cup triumph in 2011 - had complained of migraine-like symptoms for much of this month and underwent a scan on Monday.
The Blues, his Super 15 club, confirmed on their official website that Weepu's condition was not as a result of him playing rugby and that he is expected to make a full recovery.
Blues Doctor Stephen Kara said: "Piri will be out of rugby for a minimum of four weeks while we continue to investigate this condition."
Head coach Sir John Kirwan added: "Piri and his family have the full support of the organisation.
"He's getting the best possible care and advice and we are grateful this has been picked up by our medical experts, as often minor strokes remain undetected."
Weepu will be absent for at least four of the Blues' matches although he could be back playing before New Zealand next take to the field on June 7 against England.
Weepu said on Twitter: "Thanks for all the support guys, much appreciated. I'm sweet, looking forward to getting back on the park as soon as possible.. #JahBless".