"He can stay... if he wants to. We'll give him a couple of days for him to think about that and make that decision.
"It's not a great way for a great player to play his last test match if he's going to retire so it is disappointing for him but sport's like that, it can be quite cruel."
The All Blacks have been pleasantly suprised by the strength of the opposition in a so-called weak pool, and probably by the fact that they have been reasonably lucky with injuries so far, Woodcock apart.
Wyatt Crockett will be the likely starter now, with Charlie Faumuina, who plays on the other side of the scrum, having recovered from his minor hamstring issue.
"We've always talked about it - the 10 guys we've left at home - that we'd be using some of them," Hansen said of his back-up players in New Zealand. "It's a physical game played at high speed so people are going to get injured.
"He's an unsung hero, Woody," Hansen added. "He played his first test a long time ago [2002] but his real coming was against France in Paris [in 2004]. We'd strugged to beat Wales in the previous test [26-25] and he'd come under quite a bit of flak. The next game was the French and he totally outscrummed them and took a lot of heart out of that.
"Woody just got better and better and he's been a great player. He's a very mobile footballer and a skilled rugby player. He can reflect on his career at some point when he's ready to do that with a lot of satisfaction and New Zealanders can be very proud of him."
Veteran midfielder Conrad Smith said Woodcock was coping well with the disappointment, considering. "You'd never know it from him - that's the way it is," he said. "Even hearing him talking to his wife on the bus behind me [after test] ... he said 'oh well, these things happen'. It's tough, but he'll cope with it. It will be a big loss for us and we'll be hurting for him for sure."
Hansen said Woodcock had received a blow to the back earlier in the test which could have contributed to an injury he has been reasonably vulnerable to in the past.
The All Blacks will fly to south Wales today and will base themselves in Swansea ahead of their quarter-final in Cardiff on Sunday morning NZT.
They are fortunate to get an eight-day turnaround, with their opponents - France or Ireland - getting two fewer days to prepare.
It's a bonus for the All Blacks, which they plan to use wisely in terms of freshening up, Hansen said.
As for the penalties dished out against the All Blacks scrum by Irish referee John Lacey at St James' Park, Hansen was clearly frustrated by some of the rulings.
Asked if they were a concern or just "one man's opinion", Hansen replied: "Don't get me started on one man's opinion. Obviously there's stuff going on but when the surface is like that people are going to slip over. That's all I'll say, I don't need a fine at this point."
- By Patrick McKendry in Newcastle
