The New South Wales Blues have been forced into a late reshuffle ahead of State of Origin II, with young centre Casey McLean ruled out after suffering a training injury just days before the series-deciding clash at the Melbourne Cricket Ground (MCG).

McLean sustained a strain to his right quadriceps muscle during a training session at Polytec Stadium in Gosford on Saturday morning. Medical staff subsequently assessed the injury and determined that the 20-year-old would be unable to take his place in the squad for Wednesday night's match.

The setback is particularly disappointing for McLean, who had been preparing for what would have been his first State of Origin start after impressing during his debut appearance earlier in the series.

Originally selected to replace injured Stephen Crichton, McLean had earned widespread praise for his composure and maturity despite his limited experience at representative level. His rapid rise through the ranks had made him one of the Blues' most exciting emerging talents.

With McLean unavailable, Tolu Koula has shifted from the wing into the centres, while Mark Nawaqanitawase has been promoted into the starting side for his State of Origin debut. Dolphins winger Jack Bostock has also been brought into the extended squad as additional cover.

The injury compounds an already disrupted preparation for New South Wales.

The Blues had previously lost Crichton to a shoulder injury, forcing coach Laurie Daley to reorganise his backline. Despite the latest blow, team officials have expressed confidence in the squad's depth and ability to adapt.

McLean's absence will undoubtedly be felt. The Penrith Panthers youngster has enjoyed a breakout season, showcasing powerful running, strong defensive instincts and remarkable composure beyond his years. Many within the game viewed his selection as evidence of a bright future at both club and representative levels.

While the disappointment is significant, the injury is not believed to be long-term, and the focus will now shift to ensuring McLean receives the appropriate rehabilitation before returning to action for Penrith.

Meanwhile, there was positive news regarding Mitchell Moses, who trained with the squad and remains on track to feature after overcoming concerns surrounding a hamstring issue.

The Blues enter Origin II carrying a 1-0 lead in the series after their dramatic victory in Sydney. A win in Melbourne would secure the shield, while Queensland will be desperate to force a decider in Brisbane later this month.

For McLean, the timing of the injury is heartbreaking. After working tirelessly to establish himself among rugby league's elite, the opportunity to start in one of the sport's biggest arenas has been temporarily taken away.

However, teammates and coaches remain optimistic that the talented youngster's Origin journey is only just beginning.

At just 20 years of age, McLean is widely expected to feature prominently in New South Wales' future plans. Missing Origin II may be a painful setback, but few doubt that he will have many more opportunities to represent the Blues on the game's biggest stage.