Highlanders coach Jamie Joseph has indicated Adam Thomson will end his All Blacks career and move overseas.

Thomson's future has been the subject of intense speculation in recent weeks with his contract due to expire with the New Zealand Rugby Union this year.

The versatile 28-test flanker is thought to have been weighing up a lucrative move to Japan.

Unless Thomson, who was courted by the Blues for next year, makes an unlikely 11th hour u-turn, Joseph is resigned to losing one of his most valuable assets.

New Zealand Super Rugby teams unveil their 28 protected players next week and Joseph is not expecting his to inculde Thomson, who will turn out for Otago tonight in the NPC championship final against Counties Manukau in Pukekohe.

It could be his last match on New Zealand soil.

"Adam hasn't committed to New Zealand rugby so it's difficult to select him. That indicates he's heading overseas," Joseph told Fairfax Media.

"He's been a great servant and he will be sorely missed."

After appearing in all three victories over Ireland in June, Thomson fell out of favour with All Blacks coach Steve Hansen, playing just one match - 15-minutes - off the bench against South Africa in Johannesburg as Liam Messam nailed the blindside flanker role.

"If he's not playing test matches then he's not playing the level of rugby he's hoping to get," Joseph said.

Thomson's likely defection places his spot on the All Blacks end-of-year tour in jeopardy.

Hansen may feel obligated to blood another loose-forward option, such as the Crusaders' Luke Whitelock or Blues' Luke Braid, rather carry a player who will depart the New Zealand scene, when the 32-man squad is named on Monday.

At 30, Thomson may have sensed this was the right time to cash in off-shore, but his move would take some of the gloss off Joseph's remarkable off-season recruitment drive which landed Ma'a Nonu, Tony Woodcock and Brad Thorn.

He has been one of the Highlanders' best players in the last two seasons and continues to flourish at Super Rugby level.

"He's a quality player, there's no doubt about that," Joseph said.

"He's been a big part of our resurgence down here in the deep south at the Highlanders. His play is going to be really missed within the team, but as always happens in New Zealand it will give some else another opportunity."

Joseph has empathy for Thomson's predicament and, for that reason, gave him space to make the decision.

In his playing career, many thought Joseph left the All Blacks too early. He went on to spend eight years in Japan.

"I respected his time and the options he was considering. I respect the decisions he's making because I've made those same decisions as a rugby player," Joseph said.

"Having been there and done that I stepped away. I knew if he stayed in New Zealand he would play for the Highlanders."

- © Fairfax NZ News