Speaking to Martin Devlin on Radio Sport this morning, Hansen said McCaw broke the rib in either the first or second test, but believed it was just badly bruised. An X-ray yesterday revealed the true extent of the damage.
"He said he had a sore rib and the doctor looked at it but he didn't think it was broken, just badly bruised, so he played in the last one and was really sore after that so he's obviously done some more damage to it in the third test," Hansen said.
"It was definitely a courageous effort to be out there and doing what he does."
McCaw will now be unavailable for the Crusaders' final three round-robin matches.
If flanker McCaw had been ruled out of the 36-13 victory at Waikato Stadium, the All Black selectors would have faced a selection conundrum.
Sam Cane, McCaw's back-up, has a knee injury and won't be available for the Chiefs for three weeks at least, with Matt Todd only just back from a calf injury for the Crusaders.
Hansen said No 8 Kieran Read, who played the first half in Hamilton, would be managed carefully by the Crusaders after his concussion lay-off.
The Crusaders play the Hurricanes in Wellington on Saturday and the Blues in Christchurch the week after, with Read unlikely to play the full 80 minutes in either.
Fullback Israel Dagg is unlikely to be available to play the Hurricanes for Todd Blackadder's team due to his knee problem.
- Patrick McKendry of APNZ
