England left Lord's with concerns not just for the defeat against Australia but the fitness of several members of their squad.

Partially due to earlier results - notably the defeats against Pakistan and Sri Lanka - England have been persuaded to pick their first choice XI whenever possible rather than providing rest to key players. As a consequence, there is a real danger that a couple of those key players could be below their best - or even unavailable - for the crucial last couple of group matches against India (Sunday) and New Zealand (Wednesday). England may need to win both games to ensure themselves of a semi-final place.

The most pressing concern may well be over Jofra Archer. The fast bowler, England's leading wicket-taker in this World Cup, passed a fitness test ahead of Tuesday's game but then looked stiff and below his best in the field. The England management have confirmed he has "tightness to his left side" and "will continue to be assessed ahead of the India match."

Archer is a precious talent for England. The pace he generates and the skills he possesses mean he should have a big role for England in all formats for much of the next decade. England will, therefore, have to think very hard before taking any further risk with his fitness. A side strain could rule him out not just of the remainder of this tournament but much of the Ashes that follows, too.

There are also concerns over Adil Rashid. He came into the tournament suffering from a sore shoulder and has never at his best as his bowling average (51.85) and economy-rate (5.76 runs per over) illustrate. Both are the worst figures by England bowlers in this tournament.

Rashid pulled out of an event at which he was due to appear on Wednesday in order to have further treatment from the England physio. While the team management have confirmed he is "expected to be available for selection on Sunday", there must be concerns whether he is able to bowl at his best.

There is better news on Jason Roy. The England management say he is "making good progress from his hamstring injury". He batted in the nets on Tuesday and took part in shuttle runs on the outfield. It remains too early to know whether he will play on Sunday, but he is expected to train on Friday and Saturday. Given James Vince's travails - he is averaging 13.33 at the top of the order - England will be keen to see Roy return if at all possible.

Ben Stokes, meanwhile, is confident he will be fine for Sunday. He received treatment on his calf while batting on Monday, but insisted it was not serious. Stokes, who struggles to eat and drink during games, is a habitual sufferer of cramp as he tends to be heavily involved with bat, ball and in the field.

George Dobell is a senior correspondent at ESPNcricinfo