Peter Betham of the Rebels is tackled by Willi Heinz of the Crusaders during their Super Rugby trial match.

Luke Romano of the Crusaders breaks through a tackle during the Super Rugby trial match against the Melbourne Rebels.

Zac Guildford of the Crusaders is tackled by Stirling Mortlock of the Rebels during their Super Rugby trial match.

Luke Romano of the Crusaders breaks through a tackle during the Super Rugby trial match against the Melbourne Rebels.

Crusaders right wing Sean Maitland is knocked over by Blues fullback Isaia Toeava and flanker Jerome Kaino at Eden Park.

Crusaders right wing Sean Maitland scores the opening try of the match against the Blues at Eden Park.

Sonny Bill Williams chats with the fans after the game against the Waratahs at Trafalgar Park.

Brad Thorn of the Crusaders is tackled by Kane Douglas of the Waratahs.

Crusaders players celebrate a try during the round three Super Rugby match against the Waratahs at Trafalgar Park.

Israel Dagg of the Crusaders passes during the round three Super Rugby match against the Waratahs at Trafalgar Park.

Fans show their support for the Crusaders at Trafalgar Park in Nelson.

Crusaders Sean Maitland is caught in a Waratahs tackle late in the second half.

The Crusaders' Matt Todd clears the ball as he is caught in a Waratah's tackle.

Sonny Bill Williams of the Crusaders beats the tackle of Dave Dennis and Ben Mowen of the Waratahs at Trafalgar Park.

Crusader Tom Marshall looks to dissect the Brumbies defence during their Super Rugby match at Trafalgar Park, Nelson.

The Crusaders' Chris Jack in his 100 Super Rugby match looks for space against the Brumbies.

Israel Dagg looks to make a break for the Crusaders against the Brumbies at Trafalgar Park, Nelson.

Israel Dagg looks to make a break for the Crusaders during their match with the Brumbies at Trafalgar Park, Nelson.

Crusader Andy Ellis makes a break to set up Sean Maitland during their Super Rugby match against the Brumbies at Trafalgar Park, Nelson.

The Crusaders' Sonny Bill Williams gets some special treatment after the victory over the Brumbies in the Super Rugby.

Tony Brown of the Highlanders passes during the round five Super Rugby match between the Highlanders and the Crusaders at Carisbrook, Dunedin.

Nasi Manu of the Highlanders makes a break during the round five Super Rugby match between the Highlanders and the Crusaders at Carisbrook, Dunedin.

Zac Guildford of the Crusaders makes a break during the round five Super Rugby match between the Highlanders and the Crusaders at Carisbrook, Dunedin.

Matt Todd of the Crusaders tries to score during round five Super Rugby match between the Highlanders and the Crusaders at Carisbrook, Dunedin.

Josh Bekuhis of the Highlanders is tackled during the round five Super Rugby match between the Highlanders and the Crusaders at Carisbrook, Dunedin.

Crusaders winger Sean Maitland soars over to score the first of his two tries against the Sharks at Twickenham.

Zac Guildford, Robbie Fruean, Dan Carter and Andy Ellis celebrate after Carter crossed for his try against the Sharks.

Winger Sean Maitland celebrates his first try in front of the Twickenham crowd.

Sharks and Crusaders fans mingle before their historic Super Rugby match kicked off at Twickenham.

Fans at Twickenham don't forget what the Crusaders-Sharks match is all about.

All Blacks coach Graham Henry and NZRU chief executive Steve Tew are avid spectators at the Crusaders-Sharks Super Rugby match at Twickenham.

Crusaders flanker George Whitelock holds off Sharks opposite number Keegan Daniel during the Super Rugby match at Twickenham. Matt Todd looms in support.

Former All Blacks halfback Justin Marshall strolls to Twickenham to commentate on the Super Rugby match between his old side, the Crusaders, against the Sharks.

Crusaders winger Sean Maitland scores the decisive try to seal victory over the Sharks at Twickenham.

Sonny Bill Williams scores the first try of the match for the Crusaders.

Crusaders' Richie McCaw is taken down by the Chiefs' Tim Nanai-Williams.

Robbie Fruean of the Crusaders breaks through the tackle of Shaun Treeby of the Highlanders during the round 10 Super Rugby match in Nelson.

Highlanders halfback Aaron Smith gets his pass away during the round 10 Super Rugby match against the Highlanders at Trafalgar Park in Nelson.

Crusaders back Israel Dagg is tackled by James Paterson of the Highlanders during the round 10 Super Rugby match at Trafalgar Park in Nelson.

Zac Guilford of the Crusaders is tackled by Aaron Smith of the Highlanders during the round 10 Super Rugby match at Trafalgar Park in Nelson.

Nasi Manu of the Highlanders runs with the ball during the round 10 Super Rugby match at Trafalgar Park in Nelson.

Matt Todd of the Crusaders is tackled by Jarrad Hoeata of the Highlanders during the round 10 Super Rugby match at Trafalgar Park in Nelson.

Zac Guildford of the Crusaders scores the first try of the game against the Highlanders.

Nathan Sharpe of the Force looks to break through Mat Berquist and Chris Jack of the Crusaders.

Mat Berquist of the Crusaders looks to pass against the Force.

Zac Guildford of the Crusaders gets tackled by Pat Dellitt and Brett Sheehan of the Force.

Robbie Freuan gets on the move for the Crusaders.

Crusaders coach Todd Blackadder looks on as his charges record a memorable win in South Africa.

The Crusaders start the celebrations after defeating the Stormers 20-14 at DHL Newlands.

Ashley Johnson of the Cheetahs on the charge against the Crusaders.

Ryan Crotty of the Crusaders and Adriaan Strauss of the Cheetahs tangle.

Robbie Fruen tackles Tim Nanai-Williams during the Super Rugby match between the Crusaders and Chiefs played at McLean Park, Napier.

Richard Kahui is tackled in the Super Rugby match between the Crusaders and Chiefs played at McLean Park, Napier.

Richie McCaw is tackled by Sam Cane in the Super Rugby match between the Crusaders and Chiefs played at McLean Park, Napier.

Richie McCaw loses the ball in the tackle in the Super Rugby match between the Crusaders and Chiefs played at McLean Park, Napier.

Sitiveni Sivivatu is tackled the Super Rugby match between the Crusaders and Chiefs played at McLean Park, Napier.

Sona Taumalolo is ankle tapped by Dan Carter in the Super Rugby match between the Crusaders and Chiefs played at McLean Park, Napier.

Richie McCaw of the Crusaders reacts after the team's defeat by the Reds.

Will Genia of the Reds scores a try past Zac Guildford of the Crusaders.

Brent Ward of the Crusaders scores a try past Quade Cooper of the Reds.

Will Genia of the Reds runs at the tryline to score against the Crusaders at Suncorp Stadium.

Kieran Read of the Crusaders is tackled by Peter Saili of the Blues.

Tom Marshall of the Crusaders is tackled by Jared Payne of the Blues.

Luke McAlister of the Blues and Robbie Fruean of the Crusaders clash for the ball.

Robbie Fruean of the Crusaders tries to get between Peter Saili and Jerome Kaino of the Blues.

Robbie Fruean of the Crusaders at their game with the Hurricanes at Westpac Stadium.

Kieran Reid of the Crusaders at their game witht eh Hurricanes at Westpac Stadium.

Corey Flynn of the Crusaders at their game with the Hurricanes at Westpac Stadium.

Sonny Bill Williams tries to offload around Stefan Terblanche of the Sharks.

Tom Marshall makes a break in the first half against the Sharks.

Sonny Bill Williams makes a break in the first half against the Sharks.

Sonny Bill Williams celebrates his first half try against the Sharks with Andy Ellis.

All Black Israel Dagg's Crusaders season is over and injury has cast doubt over his place in the All Blacks' World Cup squad.

Dagg and fellow-Crusaders outside backs Sean Maitland and Adam Whitelock have all succumbed to serious and Super Rugby season-ending injuries.

The most critical is that suffered by Dagg, who pulled his quadricep muscle on May 8 against the Stormers. He returned home early and was operated on yesterday.

Getty Images WORLD CUP DOUBT?: Israel Dagg will miss the rest of the Crusaders' season and the Tri-Nations but will he be ready for the World Cup?

He is expected to be out of all rugby for three months, effectively ruling him out of the All Blacks' Tri-Nations tests and calling into doubt his readiness for selection in the World Cup squad.

A Crusaders spokesman said there was an outside chance he will be jogging again within 6-8 weeks although his damaged leg now needs a long and slow rehabilation.

Dagg had mostly been in sharp form until the injury but the quality of candidates among the All Blacks' back three means he may now struggle to force his way into coach Graham Henry's World Cup squad of 30.

Dagg, who missed the All Blacks' end-of-year tour last season with an injury to another part of his quadriceps after playing six tests in 2010, told Hawke's Bay Today he was optimistic of making a return to the field before the All Blacks selectors choose their rugby World Cup squad.

"Hopefully I can get a couple of games in for the Magpies and play my way into the World Cup.

"It's definitely not the time to be injured but if we do everything right with the rehab I could be back playing by the end of July.

"I'll just have to take each step of the rehab as it comes, get the strength back in the quad again and keep positive,'' Dagg said.

The immediate prognosis for Maitland was less clear, with the in-form winger having suffered a mid foot sprain.

While a time frame on his return was not yet available, the spokesman confirmed it is a long-term injury and he won't play for the Crusaders again this season.

It is the same outcome for Whitelock, who tore a pectoral muscle against the Stormers. It was confirmed today that his season has also come to a premature end.

The injury toll is also of grave concern to the national selectors as Dagg, and at a pinch Maitland, were in the reckoning for a position in Graham Henry's All Blacks Rugby World Cup squad.

Crusaders coach Todd Blackadder was due to announce this afternoon what his next move will be but its believed he will call in some cover from his wider training squad.

The Press/NZPA