Crotty will miss all of the southern hemisphere's Rugby Championship after he broke his thumb in the 30-26 semi-final victory over the Wellington Hurricanes on Saturday and had surgery.
He will be out of action for up to eight weeks, the Crusaders said in a statement on Tuesday.
Barrett broke his index finger and would not be able to play again for about six weeks, the nine-times Super Rugby champions added.
Both, however, should still be included in an extended All Blacks squad to be named later on Tuesday, even if they may not appear at all in the shortened Rugby Championship, which starts on July 20.
Crotty and Barrett would have missed the All Blacks' opening match against Argentina in Buenos Aires anyway, with no Crusaders considered because of the Super Rugby final this weekend.
The duo's absence could see All Blacks coach Steve Hansen extend his Rugby Championship squad from the initial 41 players he had been expected to name.
The Auckland Blues' Patrick Tuipulotu and Otago Highlanders' Jackson Hemopo are expected to be the major beneficiaries of the absence of Barrett, who might be fit for the Bledisloe Cup clash with the Wallabies on Aug. 17.
Hansen has already said he would use the Rugby Championship as an opportunity for players to press their claims for Rugby World Cup spots.
Crotty is expected to be back in early September, more than three weeks before the All Blacks play their opening World Cup match against South Africa on Sept. 21.
(Writing by Greg Stutchbury; Editing by Ian Ransom)
