Jason Roy will miss England's next two World Cup matches, against Afghanistan and Sri Lanka, and will be assessed on an ongoing basis in the lead-up to their clash against Australia at Lord's next week, after it was confirmed that he had suffered a hamstring tear during the eight-wicket win over West Indies at Hampshire Bowl on Friday.

Roy may yet be joined on the sidelines for the Afghanistan game by England's captain, Eoin Morgan, who also left the field on Friday with a back spasm. Although Morgan's condition has since improved, the ECB medical team will monitor him over the next 24 hours before a decision is taken ahead of the toss at Old Trafford on Tuesday.

The double setback is a blow to England after their most convincing victory of the World Cup to date. Roy sustained his injury while sprinting after a ball in the covers during West Indies' innings, and underwent an MRI scan on Saturday in London, in which the tear to his left hamstring was confirmed.

It is the second time this season that Roy's progress has been disrupted by injury - he missed much of Surrey's Royal London campaign in April and early May after suffering a back spasm while batting against Essex.

Since his return to action, however, he has been England's outstanding performer with the bat, picking up the Player of the Series award against Pakistan after making two fifties and a hundred in three outings, before setting up victory over Bangladesh in Cardiff last week with a formidable innings of 153 from 121 balls.

In Roy's absence, as well as that of Alex Hales - his long-term understudy who was axed from England's World Cup plans prior to the tournament due to two failed drugs tests - James Vince is set to slot in alongside Jonny Bairstow at the top of England's batting order.

Given that England beat Afghanistan convincingly in a World Cup warm-up at The Oval last month, the management may well be tempted to give Morgan more time to regain full fitness as well, after he was forced to address the media standing up at Hampshire Bowl, due to his discomfort, on Friday.

In Morgan's absence, the captaincy would pass to Jos Buttler, while Moeen Ali - who missed out against West Indies - might be the likeliest replacement in the XI.

At this stage - with five group-stage fixtures still to be played ahead of the semi-finals and final - it is highly unlikely that England would be considering any replacements to their original squad, given that neither Roy nor Morgan would be permitted to return at a later date once their injuries had healed.

Joe Denly, who was replaced in the 15-man squad on the eve of the campaign, is one of the players on standby in the event of a long-term injury.