The Harlequins' flanker Chris Robshaw will captain England in this autumn's Tests but injuries are complicating Stuart Lancaster's team selection for Saturday week's opening game against Fiji. Northampton's Dylan Hartley is likely to miss all four of England's forthcoming internationals, while his club-mate Courtney Lawes will be out of action for at least the next fortnight.

Both Saints players sustained knee injuries against Saracens last weekend and Hartley has been ruled out for a minimum of four weeks. If the combative hooker is required to prove his match fitness for his club before returning to the Test arena, he must be considered a doubtful starter even against his native New Zealand on 1 December.

Jonathan Joseph, the London Irish centre, is not expected to train until the middle of next week after suffering an ankle problem against Harlequins on Sunday. The Quins prop Joe Marler has a hamstring strain but, as things stand, Lancaster believes the latter will be available to face Fiji. If not, Robshaw could find himself leading a team containing two front-row debutants in Tom Youngs and Mako Vunipola.

That would hardly be an ideal scenario at such an early stage of the season and Lancaster acknowledged Hartley's absence would leave "a void" in his pack. "Dylan was one of our key players in the Six Nations and in South Africa, no doubt about it. In an ideal world you'd have all your players all the time but the reality is that never happens. We used 28 players in three Tests in South Africa and, with four internationals, I can guarantee it'll be around the 30 mark this time."

Nine players have already been released back to their clubs and another two are due to follow on Wednesday. Ben Youngs and Ben Morgan have both been invited to show what they can do for Leicester and Gloucester respectively this weekend, and Mike Brown, Anthony Allen, Phil Dowson, James Haskell and Jordan Turner-Hall will get similar opportunities. George Robson and Matt Mullan will also be returning home after being summoned as cover.

The rubber-stamping of Robshaw as captain, meanwhile, surprised nobody. He has led his country in all but one of the eight Tests they have played under Lancaster, who described his choice as a "no-brainer" and hailed the Quins' captain as "a real inspiration".

Robshaw insists his team have a good deal of improvement in them. "This is a great group of players who really want to be successful," he said. "We have a huge opportunity to put a marker down over the next few weeks and just from training this morning you can see how keen the boys are."