The 39-year-old Thorn was ruled out for four months after his right bicep muscles were torn from the bone early in the second half of the match against the Bulls in Dunedin almost a month ago.
But he said he still had high hopes for the eighth-placed Highlanders who could move even further up the table against the struggling Lions.
“Just realising I am not going to get to play Super Rugby again this year is really tough,” Thorn told the Otago Daily Times.
“I’ve just got to be patient. I always like to push things. But if I try and do too much, then I could damage what has been done,” he said.
The Highlanders are seventh among the top 10 teams in the competition and have scored 24 tries.
The Hurricanes are leading the try stakes with 34, while the only South African team to feature are the Cheetahs in third on 29. The 12th-placed Lions have scored the least number of tries – 12.
Looking at what separates the two teams, the Highlanders have scored just one more win with five to the four recorded by the Lions, and are leading the men from Johannesburg by 10 points – 26 against 16.
The difference comes in the six bonus points the Otago men have gathered against the zero from the Lions, who have failed to add any points in their last four clashes.
Thorn, who has decided not to call time on his career yet, revealed how a clash with Bulls fullback Jurgen Visser led to his injury, the first serious damage in almost two decades.
”I was pumped, thinking I’m the first guy here, I’m going to get that fullback. I grabbed him, but when I grabbed him he went the other way and I heard something. I just knew something had happened.”