A hamstring injury has forced Waratahs back-rower David Lyons out of the Super 14 final against the Crusaders in Christchurch on Saturday.

Lyons (pictured) injured himself a week ago but was hoping to recover in time to make his final appearance for the Waratahs before moving to Europe next season.

"The temptation for many players to play would have been huge but David's always been about the team and although this is extremely disappointing for him he didn't want to play if he wasn't 100 percent," NSW coach Ewen McKenzie said.

"Even though David won't be on the park on Saturday, his input and tactical nous will be important for the squad in the final lead-up to the match."

While Lyons failed in his bid to make the team, there was better news for Waratahs hooker Tatafu Polota-Nau, who was cleared to resume playing after missing last weekend's 28-13 semi-final win over South Africa's Sharks in Sydney.

McKenzie said Australia test hooker Adam Freier would return to the bench, providing the Waratahs with added depth in every position.

"It's an exciting blend and we won't die wondering on Saturday," he said.

The Crusaders have also changed their hooker with Ti'i Paulo replacing Corey Flynn after he broke his arm in their 33-22 semi-final victory over Wellington.

"It's obviously bad luck for Corey, but we have every confidence in Ti'i," Canterbury coach Robbie Deans said.

"He's played very well for us when given the opportunity, and I'm sure he will do so again."

The Crusaders go into Saturday's clash as overwhelming favourites to win their seventh title after beating NSW 34-7 at home in March and finishing the regular season on top of the standings.

They boast a stunning line-up packed with New Zealand internationals including All Blacks skipper Richie McCaw and fly-half Dan Carter, who are among seven Crusaders who played in the side that beat NSW in the 2005 final.

"Finals are always great, the intensity, the uncertainty is what the sport's all about," said Deans, who will be in charge of the Crusaders for the last time after accepting the job of coaching Australia.

Reuters