England’s half-back problems have deepened with Alex Mitchell a major doubt for their Nations Championship fixtures this month after suffering a hamstring injury.

Mitchell was forced off early in the first half of Northampton Saints’ 28-14 win over Gloucester, with the initial prognosis not positive for involvement in the autumn.

Steve Borthwick was already fretting over the fitness of Northampton fly half Fin Smith, who has a calf injury, while McParland suffered an issue in England camp this week.

It leaves Jack van Poortvliet likely to retain the starting No 9 shirt for England’s opener against Australia on Sunday, with Smith expected to be given until Wednesday to prove his fitness.

“Fin and Archie are both calf [injuries], Fin probably not as bad as Archie, but it remains to be seen,” Phil Dowson, the Northampton director of rugby, said.

“Mitchell has hurt his hamstring but I don’t know how bad. We have to be super-careful with Alex.”

Mitchell missed the last two rounds of the Six Nations with a hamstring issue, and was also afflicted by an injury in that area towards the back-end of the last Gallagher Prem season.

Borthwick will confirm his Nations Championship squad on Monday morning, with Bath hooker Kepu Tuipulotu another major doubt.

The 21-year-old will see a surgeon about a knee injury sustained in England training. Theo Dan, a possible alternative call-up, also lasted just 10 minutes of Saracens’ win over Newcastle Red Bulls on Saturday.

Flanker Guy Pepper and centre Benhard Janse van Rensburg have already been ruled out of the autumn. England face the Wallabies, Japan, New Zealand and a game on the inaugural Nations Championship finals weekend at Twickenham’s Allianz Stadium.