All Blacks fullback Ben Smith could miss the rest of the Super Rugby regular season with a hamstring strain in a blow for the Highlanders' title hopes but his flanker team mate Liam Squire could be set to return after a long injury lay-off.
Smith, who was hurt in the 31-31 draw against the Chiefs last Saturday, will be sidelined for six-to-eight weeks, assistant coach Glenn Delaney told local media on Tuesday.
"Just a classic rugby incident where he got caught in a tackle and overextended," Delaney said.
"All the right things are being done and he'll be back as quick as he can be with the right rehab."
Smith's injury, sustained when he slipped in a heavy tackle, threw a scare through New Zealand, with All Blacks outside back Damian McKenzie having already been ruled out of the World Cup by a knee injury.
"Six to eight weeks, from how the injury looked, you could say that was very lucky," All Blacks and Highlanders scrumhalf Aaron Smith said.
Third in the New Zealand Conference with six rounds remaining until the post-season, the Highlanders need a victory over Argentina's in-form Jaguares at home on Saturday to keep in touch with the playoff positions.
Smith, who has won 76 All Blacks caps, is playing his final season with the Highlanders before moving to Pau in France so he might never play for the Dunedin-based side again if they fail to make the playoffs.
Delaney said All Blacks blindside flanker Squire and winger Waisake Naholo had returned to training and were available for selection.
Battling hip and knee problems, Squire has not played since facing Ireland for the All Blacks in November, while Naholo has been out for a month after suffering a knee ligament injury.
Delaney suggested both would be eased in gently if selected to face the Jaguares.
"(Squire's) full of energy and enthusiasm and doing all the right things and speaking well to the group," he said.
"He's just getting through day by day but the one thing we won't do with either of those guys is that they won't be back before we think they are ready.
"We'll look after them because it's important to us and obviously to some other teams as well."