Both Liam Squire and Jason Emery have been added to an ever-growing list which has seen the side decimated. Squire injured his knee in the first half of Saturday's game against the Crusaders and will miss four to six weeks.
The team is awaiting an accurate diagnosis. Meanwhile, Emery is set to miss the remainder of the season after rupturing his Achilles.
They join a long list that includes, among others, Ben Smith, Ash Dixon, Dan Pryor, James Lentjes and Shane Christie.
Having lost their first two games, the Highlanders' match against the Blues at Eden Park on Saturday is crucial. Assistant coach Scott McLeod said Luke Whitelock was a possibility to return. Provided he got through the next few days' training he could be an option to step in for Squire at No 8. However, he acknowledged Squire was a huge loss. He had brought physicality and was an influential figure in the 30-27 loss to the Crusaders.
''We felt he had an outstanding game the other night. He motivated a lot of our players and really caused some damage.
''But in saying that we've got other players that will step into that void and hopefully bring the same intensity.''
Meanwhile, Emery had been trying to get through a strained Achilles during the curtain-raiser to Saturday's game, but ruptured it in the process.
Openside flanker and hooker remain the hardest-hit areas. Both are down three players after James Lentjes dislocated his elbow and Adrian Smith tore his calf on Saturday. Otago hooker Sekonaia Pole, who came off the bench at the weekend, was likely to come into the squad.
At openside flanker Otago loose forward Dillon Hunt had been with the squad, but it was not planning to bring in anyone else.
Meanwhile, Ben Smith had been back into some light training and a decision would be made later in the week as to his availability for this weekend.
''He's getting through his protocols at the moment,'' McLeod said.
McLeod believed the squad had capable replacements and would look to ensure the Blues did not get into the game early.
''Yes we do have injuries, but we've also got capable people and a really extensive squad that can fill into that. Players have always been motivated by opportunity and a lot of players are getting that so we're really happy.
''[The Blues] have a lot of X-factor across the park and they're putting that together and they can be a really powerful team. The challenge for us is to not let them start that and get into the game.''