Liam Coltman has been ruled for the rest of the year

Fringe All Black Liam Coltman has been ruled out of rugby for the rest of the year, after suffering a serious ankle injury.

Coltman, whose lone test came against Italy in Rome last November, suffered the injury during the Highlanders' Super Rugby quarter-final loss to the Crusaders.

It was feared the 27-year-old hooker had broken his ankle, but further assessments revealed a high-ankle sprain that needs surgery to repair ligament damage.

Coltman is ruled out of the selection contention for the Rugby Championship and Otago's NPC campaign.

A four-to-six month recovery window means he will also be unavailable for the All Blacks' season-ending tour of Europe.

Coltman provided injury cover during the test series against the British & Irish Lions, but didn't play, with Codie Taylor and Nathan Harris preferred in the injury-enforced absence of Dane Coles.