Hardie (24) damaged his posterior cruciate ligament (PCL) in the second half of the match between the Highlanders and a Southland invitational XV at Forsyth Bar Stadium.
Although he was training yesterday with a bandage on his knee, it was still unknown whether Hardie would be able to play in the match at the stadium on Saturday night.
The PCL was not a vital ligament in the knee and it was possible to play with it in a damaged condition.
Highlanders coach Jamie Joseph said there was still the soreness from the initial injury and it was still relatively stiff, so Hardie may find it tough to front on Saturday.
A decision would be made later in the week.
As for other options for the Highlanders in the No 7 jersey, they appear limited.
Tim Boys has a crook neck and had not played since early March.
Hugh Blake is the other specialised openside flanker in the squad but he has yet to play this season, and has played just five first-class games, making his debut for Otago last year.
Hardie has played every game for the Highlanders this season and was in impressive form, starring for the Southland invitational XV against the Highlanders.
