The Giants captain last night underwent an operation on a broken thumb, immediately ruling him out of tomorrow's engage Super League clash at Harlequins (6.05).
It's obviously a massive blow for the Giants, who are looking to end a run of four top-flight defeats and climb from fifth bottom.
Vice-captain Brad Drew will lead out the side in his absence, with Robbie Paul - who will play against brother Henry this weekend following his move from Gloucester RU club yesterday - taking midfield charge in Thorman's absence.
But head coach Jon Sharp knows losing his captain at such a crucial time is a big loss.
"It's disappointing for the team, but even more disappointing for Chris," said Sharp.
"He was hoping to enjoy a good run of form after finally getting over an ankle injury, so we all feel for him right now.
"And, to be honest, this latest news came right out of the blue.
"Chris picked up the injury during the Wigan game and, even though he was in a bit of pain in training, he didn't think it was too serious. He's a very tough kid.
"But after training yesterday, he thought he'd better get it checked out because it wasn't getting better and that's when a crack in the bone was revealed.
"The only consolation is that a surgeon was able to operate immediately, but it's still going to keep him out for six weeks."
