But he says his inability to bag a black jersey is only part of the reason he is leaving to play overseas.
Manu (26) announced earlier this week he had signed a two-year deal with the Edinburgh club and would leave the Highlanders after six seasons with the southern franchise.
The No 8 said it was not an easy decision to leave.
''I have really enjoyed my time here. It is my home. I guess, for me, I feel like it is the right time.
''My main focus is to leave on a good note and do what I can for the Highlanders,'' he said.
''I have played eight Super rugby seasons and I guess I am sort of ready for a new challenge.''
Manu said he had not thought about coming back and playing at the Highlanders once his two years with Edinburgh were up.
''I am 27 this year. If I play for a couple more years overseas, then I hope I do have a few more years in me. But I'm just ready to explore the world.''
The big No 8 has played more than 50 games for the Highlanders and wants to leave the franchise in good heart.
He said knowing his future was clear was a weight off his shoulders, and he hoped that would help his performances for the rest of this season.
Manu said he had heard only once from the All Black selectors, but to him, it was about playing as well as he could for any side for which he played.
''I heard from them a couple of years ago. They just said I had to keep working hard at my game. And that has always been it for me - to play the best I can for the team I'm playing for.''
Manu was never mentioned as an All Black candidate in recent years, despite his impressive form for the Highlanders.
He appeared to be well ahead of the likes of Luke Whitelock but injury in 2013 ended his Super rugby season.
Others were preferred that year, and he has never had a look in since.
It seems a shame a player of Manu's experience and talent is off overseas at the age of 26, but such is the depth and talent of loose forwards in New Zealand that some very good players miss out.
A professional player virtually out of school, Manu said he was not tiring of the life.
''I still enjoy it and every season that I come into, I want to play as well as I can.''
Manu will pack down at No 8 again tomorrow night but will have a new loose forward beside him, with James Lentjes coming into the side.
Hooker Ash Dixon swaps places with Liam Coltman and gets a start. Otherwise, the side is the same that played the Hurricanes last Friday.
The Stormers have been in Queenstown this week and will bus to Dunedin today. Last time they played at the stadium, in 2012, they won.