Alex Mitchell ruled out of England's Australia opener with hamstring injury

Alex Mitchell will miss England's opening Nations Championship match against Australia on Sunday, after damaging a hamstring in Northampton's win over Gloucester.

Mitchell is England's first-choice scrum-half, the player who takes the ball from the back of the pack and passes it out to the backs. He came off after 21 minutes of Saturday's 28-14 Premiership win. The hamstring is the muscle at the back of the thigh, and it is a common injury for players who sprint and change direction. Mitchell is due to have a scan on Tuesday to find out how serious the damage is.

Head coach Steve Borthwick has called up two scrum-halves in his place. Bristol's Harry Randall and Bath's Ben Spencer have both joined the squad. Spencer has only recently returned to action for Bath after shoulder surgery. Jack van Poortvliet is expected to start against Australia, with either Randall or Spencer on the bench.

Mitchell is not the only absentee. Archie McParland is also out for the Australia match, with a calf injury picked up in training with England last week. Bath hooker Kepu Tuipulotu has dropped out of the forwards through injury, and Saracens' Theo Dan comes back into the group.

There are some changes at the other end of the squad too. Max Ojomoh and Noah Caluori, who were in the group named eight days ago, are no longer part of it. Seb Atkinson, Immanuel Feyi-Waboso and Fin Smith are all in the 36-man squad, despite recent injury concerns about each of them.

The squad of 20 forwards and 16 backs gathered at Pennyhill Park, England's training base, on Monday night. Over the next few days, the medical updates and training sessions will shape the team that runs out on Sunday. For now, the changes are clear: a fresh scrum-half pecking order and a fair few new faces to settle in quickly.