The Blues, unlikely to make the Super Rugby play-offs, potentially have only three matches remaining this season, starting with a game against the Hurricanes in Wellington on Saturday.
Two matches against the Brumbies and Waratahs at Eden Park follow.
Another injury concern for Blues coach Tana Umaga is Charlie Faumuina, who started at tighthead prop in Dunedin. Faumuina has suffered a knee injury (medial ligament) and Hansen said he could be out for between one and three weeks.
Skipper Kieran Read suffered a "stinger" shoulder issue which wasn't serious, but Crusaders teammate Ryan Crotty, who started at second-five, is in doubt for the match against the Chiefs in Suva on Friday.
For Hansen, it will be a nervous wait as he says goodbye to his players before the Rugby Championship, which starts for them with a test against Australia in Sydney on August 20.
"I'm concerned about all of them, I don't want any of them to get injured," he said.
"But at the same time we can't wrap them up in cotton wool; we need them to play footy and they've got to play some big games and let's sit back and see how they cope with it. And the guys who do cope with it, that's a big advantage."