All Blacks and Crusaders skipper Richie McCaw hasn't exercised the "sabbatical clause" in his New Zealand Rugby Union contract but he will sit out the opening rounds of the Super 14.

McCaw could have exercised the clause and miss the whole tournament but he has opted for an extended holiday following the Northern Hemisphere tour and will rejoin the Crusaders' camp for the beginning of their Super 14 campaign but he will only be considered for selection until the round four home match against the Blues on March 6.

Crusaders coach Todd Blackadder said this was not a cottonwool case but he believes it would be the "last real opportunity" McCaw would get for an extended break before the 2011 World Cup.

"Richie's actually got a sabbatical clause in his contract, so he's got the right to take the whole Super 14 off," Blackadder told the New Zealand Herald.

"To his credit he doesn't want to do that. He wants to play."

McCaw played just seven games for the Crusaders last year due to a combination of injuries, so it is not as if Blackadder is new to adjusting to life without McCaw.

"[Richie] recognises that he really needs to look after himself. On reflection, I think it's a really positive thing. He doesn't want extended time off, he wants to play but he needs that first three weeks to make sure he is fit and is raring to go," Blackadder said.

"He's not skiving off anywhere, he will be with us for the duration of the campaign, he will train alongside the team, he just will not be available to play until March."

There was no suggestion McCaw was nursing injuries that might need attention, rather Blackadder said it was more a case of freshening up mentally.

"I think feeling mentally fresh is as important as being physically fresh. He's just such a massive contributor. I know how much he puts into the Crusaders and I have no doubt he puts more into the All Blacks. He's a busy man off the field, too, so if he can come back from Europe and not feel he has to rush back into training, we will all benefit from it."