A hamstring injury forced him off the field in England’s win against West Indies and he was ruled out of matches against Afghanistan and Sri Lanka.
Australia was the initial target for Roy’s return, but Monday morning’s scan results show he will have to aim for a comeback against India on Sunday instead.
Roy returned for a bat in the nets in England’s training session at Lord’s ahead of the Australia tie after watching the empathic win against Afghanistan and the shock defeat against Sri Lanka, but was not deemed fit enough to play a full match.
England missed their mainstay opening batsman in both games, with James Vince, his replacement in the side, falling for 26 and 14 respectively.
“He's Jason Roy. Of course he's a big loss,” said Eoin Morgan. “He's an outstanding performer before us, the way he plays. Epitomises the way we play as a group. He's been in the team for a very long time.
“I'm confident we have the batting covered. James Vince is an extremely talented, gifted player. You can see that from just watching him.
“We have every faith in him to go on and get a score at some stage, to continue playing in his own way. It's important that he does that.”
The latest scan showed that Roy was making good progress, but Trevor Bayliss has vowed not to include the Surrey batsman until he was fully fit to not jeopardise his involvement later in the tournament, so Vince will keep his place.
"If someone of Jason's ilk is not playing of course you're going to miss someone like that," said Bayliss.
"That's the game. He's injured and I'm not exactly sure when he'll be back, but we are looking forward to him coming back.
"We're not going to risk him that's for sure. We'll play each game as it comes and get the medical people to let us know whether they think he is right for the next game. If he's not, well we'll do the same heading into the next game."
England's defeat against Sri Lanka, their second of the tournament, has increased the importance of winning their final three fixtures, Australia, India and New Zealand, if they are to safely qualify for the knockout stage of the World Cup.
The hosts sit on eight points from a possible 12 with nine or 10 thought to be enough to secure qualification to the semi-final.
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