The Highlanders have lost the services of veteran lock Brad Thorn to injury for up to a month.
Thorn, 39, damaged rib cartilage while tackling Blues opposite Liaki Moli midway through the first half of the Highlanders' season-opening 29-21 win in Dunedin on Saturday.
The 59-Test former All Black is expected to be sidelined for three to four weeks, meaning a possible return in a home game against either the Western Force (March 15) or Hurricanes (March 22).
Thorn's starting spot is likely to be taken by Southland lock Josh Bekhuis, alongside Jarrad Hoeata.
Elsewhere, promising Argentina international prop Matias Diaz is available to play against the Chiefs in Hamilton on Saturday in the clash of New Zealand's two unbeaten sides.
Diaz, 20, didn't get a transfer clearance in time to face the Blues but Highlanders management has received the necessary paperwork.
Wing Richard Buckman has been promoted to the full Highlanders squad after starting the season in the wider training group.
He replaces Buxton Popoali'i, who has pulled out of all rugby in 2014 because of a heart problem.
