Newcastle captain Kurt Gidley has been ruled out of the Knights’ round two clash with North Queensland with a back injury in a major blow ahead of Saturday night’s clash. Gidley was forced from the field with back spasms during the Knight’s 42-8 win over Penrith on Sunday. He was cleared of any serious damage after undergoing scans on Monday and named at fullback on Tuesday. But the Knights today decided to take no risks with the injury responding slower than expected to treatment. Gidley has been replaced by former Wests Tigers fullback Shannon McDonnell. Newcastle spokeswoman Michelle Smit said Gidley was only ever a 50 per cent chance of playing when Rick Stone named the side. “He was hoping the back would have settled down by now, but it hasn’t responded as well as he hoped so he’s out,” she said.