Webb was injured in training a week ago and missed last Saturday's engage Super League Grand Final win over St Helens.

He underwent spinal surgery yesterday and is likely to be out of action for between five and six months – ruling him out of New Zealand's World Cup squad and causing him to miss the start of next season and – almost certainly – Rhinos' World Club Challenge clash with Manly Sea Eagles.

McClennan said: "All our thoughts are with Webby at the moment. He is a special guy and someone who we all love dearly. We have got an excellent medical staff and they will be making sure that Brent receives the best possible treatment and comes back stronger than ever."

Rhinos phsyio Meirion Jones said: "Brent has had microdiscectomy on acute disc herniation. It is hoped that the surgery will clear up Brent's current symptoms, however key will be a sustained period of five to six months rehabilitation to complement the surgery to get Brent back to full fitness."