A strained hamstring has sidelined Crusaders lock Brad Thorn from Saturday's key Super 14 match against the Blues in Auckland.

Thorn pulled up sore at training on Thursday morning and will be replaced by Michael Paterson from the reserves, while Ross Filipo comes onto the bench.

With the exception of Thorn, coach Todd Blackadder will be able to field the rest of the starting line-up that dumped the Reds 32-12 last week.

And he has welcomed back flanker George Whitelock who has not played since injuring a knee in mid-April.

Whitelock was passed fit after Thursday's training.

"It's great to have George back in the frame for us. He had been playing very well for us until his injury but the way Jonathan (Poff) stepped in has been magnificent," Blackadder said.

"We are preparing for a big challenge against the Blues. They are tough to beat at Eden Park and will have one or two points to prove on Saturday night," he said.

The Blues, whose casualty ward is filled to overflowing, have at least been able to field a settled starting backline.

In the team announced on Thursday, Chris Smylie, Jimmy Gopperth, Isaia Toeava, Joe Rokocoko, Rene Ranger and Rudi Wulf will back up from the 15-37 loss to the Brumbies last week.

With the exception of Smylie, that backline also started two weeks ago against the Hurricanes.

But coach Pat Lam is still without injured forwards such as Ali Williams, Anthony Boric, Onosai Auva'a, Chris Lowrey and Josh Blackie.

Stalwart flanker Justin Collins, who has missed much of the campaign recovering from concussion, is finally available but bracketed with Peter Saili at blindside flanker.

There was some uncertainty surrounding prop Tony Woodcock but he will start, giving the Blues scrum some stability in concert with fellow All Blacks John Afoa and hooker Keven Mealamu.

The Crusaders, on 37 points, are fourth in the standings, ahead of the Brumbies, also on 37, on points difference.

The ninth-placed Blues playoffs hopes disappeared with last week's defeat to the Brumbies.

The Brumbies play the second-placed Chiefs in Hamilton on Friday night.

Brought to you by AAP © 2024 AAP