The Crusaders captain Richie McCaw is a late withdrawal from their potential Super Rugby classic against the South African conference leading Stormers in Cape Town on Sunday morning due to concussion.
McCaw took a knock to the head in the match against the Western Force in Perth last weekend.
He had a few headaches during the week, though they lessened as the week went on.
But it was decided early Saturday morning that McCaw would not take part in the match at Newlands.
Crusaders head coach Todd Blackadder says McCaw would be monitored in line with head injury protocols but was likely to be available for next weekend's match against the Cheetahs in Bloemfontein.
Matt Todd will play at openside flanker in McCaw's place while Jonathan Poff comes onto the reserves bench.
Returning number eight Kieran Read will captain the side.