England captain Eoin Morgan has warned Australian pair David Warner and Steve Smith they will not be "accepted back into the cricket community straight away".

England face Australia in their World Cup clash at Lord's on Tuesday, with Morgan insisting he will not give supporters any instructions on how to treat the two batsmen, who are back in action having served bans for ball tampering.

Rejecting the idea of giving orders to the crowd, Morgan said: "I'm not expecting anything. I think fans and supporters up and down the country will have different reactions, as they will around the world. So we'll see.

"Supporters pay a lot of money. And sport is beautiful in many ways, because it attracts people from far and wide.

"And you often see crowds offering support to both sets of players in the grounds."

Morgan did, however, warn Warner and Smith they will not be welcomed back into cricket's fraternity with open arms, despite returning to international action.

"You don't know how sports fans will react," said Morgan, who revealed England opener Jason Roy would miss the match through injury.

"Just because two guys have been punished, served their punishment and returned to play, it doesn't mean they will be accepted back into the cricket community straight away. It will take time."

Jonny Bairstow accused Australia of double standards over asking fans to lay off Warner and Smith, despite previously urging their own supporters to dish out some stick to Stuart Broad.

Morgan refused to be drawn on his team-mate's views, but suggested Australia's current backroom staff have a more measured approach than previous set-ups.

Asked for his view on on Bairstow's comments, Morgan said: "I don't have a view on it. I think every instance is different, every team is different.

"Year on year it's a different set of circumstances.

"I believe that was a long time ago under a different regime. I don't know."

Morgan revealed Roy has received a positive outlook from his scan on a torn hamstring, but admitted he could not offer a specific timescale for the opener's return.

Roy returned to the nets on Monday but he will not be fit to face Australia.

"Jason went for a scan this morning. It's all positive news, he won't be fit for tomorrow," said Morgan.

"We'll monitor his progress in the week. To put one game on it (for Roy's return) I don't think is sensible, let's just see how it goes."

Roy has been absent from his side's last two matches and was heavily missed during the shock defeat to Sri Lanka on Friday.

Monday's scan showed the 28-year-old was making good progress in his recovery, but head coach Trevor Bayliss has vowed not to include the Surrey batsman until he is fully fit, meaning another chance for James Vince.

Morgan added: "It's Jason Roy, of course he's a big loss. He's an outstanding performer for us.

"But I'm confident we have the batting covered, James Vince is an extremely talented, gifted player. You can see that just watching him.

"We've every faith in him to go on and get a score at some stage."

Defeats to Sri Lanka and Pakistan leave England needing perhaps two wins from their remaining three round-robin matches against Australia, India and New Zealand to reach the semi-finals.

But Morgan rejected the idea Tuesday's clash at Lord's is already a do-or-die situation for England.

"It's not must-win yet," said Morgan.

"We don't need to win every game to get to the semi-final."