Canterbury co-coach Reuben Thorne says they only found out during this afternoon's training session, ahead of his side's Mitre 10 Cup match against Wellington this weekend.
"It's a fantastic opportunity for him. We thought he might be in that position already.
"He's one of those guys who just works and works and works. Underrated as a lineout forward.
"His work rate's massive he gets around the field and makes a lot of tackles. I don't think it'll be an issue for him at a high level – he's got the talent, he's got the desire and he's as tough as nails."
Thorne says it wasn't the biggest surprise to lose Dunshea to All Blacks selection.
"The locking stocks, it's a challenging area and we know there's a couple of guys with injury concerns… we always felt our locks were probably at risk, particularly Mitch.
"It's a bit of a blow for us to be honest, because he's a key part of our group."
Meanwhile, Hurricanes midfielder Ngani Laumape, Crusaders captain Scott Barrett and Otago hooker Liam Coltman have joined the camp.
Laumape (broken forearm) and Barrett (toe) will have their respective injuries assessed but both are expected to be among the 11 players added to the original 35-man squad, along with Wellington midfielder Peter Umaga-Jensen who is in line to replace the injured Braydon Ennor, for the Rugby Championship.
Coltman has been called in to cover Asafo Aumua who is recovering from a head knock suffered while playing for Wellington. Beauden Barrett is also back with the squad following the birth of his daughter, Billie Rose.
