Coach Graham Henry told a press conference today that "it's just one of those things that happens".
Henry says Cruden is now the number one first-five in the squad while Piri Weepu is most comfortable at halfback and can navigate the side from there.
He said Donald was whitebaiting when he got the call-up while Gear was travelling with his family.
All Black doctor Deb Robinson says the lack of rest for players has contributed to the injury toll due to playing 10 tests in 12 weeks.
It is a bitter blow for veteran fullback Muliaina who played his 100th, and now last, test on Sunday. Muliaina played in the last two Rugby World Cups in which the All Blacks failed to reach the final on both occasions.
Muliaina broke down as he spoke of his bitter disappointment today.
"I know I won't be back," he told media.
"I'm just proud to be a kiwi and proud to be an All Black."
Muliaina, 31, has signed a two-year deal with Japanese club NTT Docomo and will start with the club next season.
Getting to 100 tests has slightly softened the blow of being out of the World Cup. He said he will miss the people the most.
"What other job can you get people out of their seats and cheering you on?"
On a positive note Henry confirmed injured duo Israel Dagg and Richard Kahui are fit for selection for Sunday's semifinal clash against Australia.
- HERALD ONLINE