Todd Blackadder has called for an immediate change to one of rugby's concussion laws after an incident which saw his team disadvantaged in the final minutes of their loss to the Chiefs in Christchurch on Saturday.

The unfortunate sequence of events occurred when Tim Boys, the openside flanker, was replaced after 67 minutes by Reed Prinsep, who was almost immediately knocked unconcious following an accidental clash of heads.

The concussed Prinsep was taken off the AMI Stadium pitch on a stretcher and straight to hospital after a break in play of at least 10 minutes, following which the Crusaders, 21-22 down at the time, asked to replace him with Boys, only to be told by referee Chris Pollock that the law didn't allow it.

Only those going off for blood or a concussion test are allowed to be replaced by a substituted member of the starting XV, meaning the Crusaders were forced to send replacement halfback Leon Fukofuka into the unfamiliar position of flanker.


The Chiefs went on to score another try through Sam Cane for a 27-21 victory and, while he wasn't suggesting the Prinsep injury controversy was the cause of the defeat, coach Blackadder was critical of a law which appears to defy logic.

"I think common sense needs to prevail here," Blackadder said.

"If Reed had been able to say 'I've had a head knock, I need to come off for a concussion test', we would have been able to replace him with Tim. But the fact that he was knocked unconscious meant we weren't able to do that.

"The law needs to be amended straight away because player welfare has to come first and teams shouldn't be penalised for players being knocked unconscious."

Blackadder, who will this week prepare his side for the visit of a Blues team on a high from their 33-31 victory of the defending champion Highlanders, said the law as it stood was vulnerable to gamesmanship.

He said there was nothing stopping Prinsep's replacement Fukuoka making a tackle and complaining of a sore head which would have resulted in a concussion test and Boys coming straight back on.

The match between two of the fiercest rivals in Super Rugby was a testy affair, with halfback Andy Ellis engaged in a running battle with first-five Aaron Cruden, and lock Sam Whitelock needing treatment on an eye injury after contact with halfback Tawera Kerr-Barlow's boot.

The citing commissioner decided Kerr-Barlow had no case to answer.

For Tana Umaga's Blues it was straight back to work following their thrilling come-from-behind victory over the Highlanders at Eden Park.

The message for the players from the coaches was that they had achieved little yet, and they went back to training yesterday for Friday night's match against the Crusaders in Christchurch.

The Highlanders, meanwhile, were on an early morning flight to Dunedin where they will play the Hurricanes, thrashed 52-10 by the Brumbies in Canberra, next Saturday night.