Morgan Knowles has been ruled out of England’s World Cup opener with Tonga through injury.

The Dolphins forward has suffered an injury in training in the days leading towards Saturday’s game against the Tongans and has been ruled out of the contest, a huge blow for Brian McDermott’s side heading into a crucial group stage game.

Knowles had been named as starting prop on Tuesday, with the former St Helens ace set to line up alongside Max King in spearheading England’s pack against a powerful Tongan outfit.

But he has now been ruled out, a setback amplified by the absences of several other key forwards. Matty Lees is missing the tournament through injury while Morgan Smithies has already withdrawn from the squad after suffering a hamstring injury which brought his campaign to an end before it had even started.

Ben Currie is now set to be named in the matchday squad having been initially left off the six-man bench. Luke Thompson appears likely to be promoted to a starting role with Talty moved to the bench alongside Jez Litten, Jack Welsby, Sam Walters, Ethan Havard and Matty Ashton.

England suffered other withdrawals in the pack before the tournament, most notably in the shape of Wakefield pair Mike McMeeken and Caleb Hamlin-Uele, leaving McDermott without a string of key players for the tournament.

That said, Knowles loss feels like a particularly bad one, such has been his importance to the England side over several years. He comes into the tournament off the back of an excellent debut season in the NRL too following his move from Saints. He played 25 times for Kristian Woolf’s Dolphins as they made the semi-finals on the NRL play-offs.

Knowles is expected to be fit for the game against France next week and will remain in the squad. England subsequently take on France and Papua New Guinea in their quest to advance to the semi-finals. However, with Tonga appearing to be their toughest test in the opening stage of the tournament, his absence is undoubtedly a tough one for England to stomach ahead of Saturday’s contest in Perth.