Joe Root is expected to be fit to play in Sunday's one-day series opener against Australia in Melbourne, as he recovers from the illness that hospitalised him during the fifth Ashes Test.
Root is still feeling the after-effects of the stomach bug, which forced him to retire hurt twice on the final day in Sydney with bouts of vomiting and diarrhoea.
The 27-year-old returned to training on Wednesday, but only had a light run around and warm-up before returning to the team hotel - just three days after spending six hours on the field in record-breaking Sydney heat.
The Test captain is not expected to play in England's warm-up match against a youthful Cricket Australia XI on Thursday, but team officials say he's currently recovering well enough to take his place for Sunday's game.
"He's obviously a lot better than he was on Monday," wicketkeeper Jos Buttler said.
"He's up and about so I think a few more days and his bug should have gone. He's a huge part of our side so we're desperate for him to be fit and well.
"I'm sure he will rest up and try and get his energy back."
Root's illness forced him to sleep through the closing stages of Monday's Test loss, and the English squad must find a way to recover from the nightmare of the 4-0 series defeat.
Seven players who featured in the Tests for England have been named as part of a one-day squad building towards next winter's home 50-over World Cup.
England have won just one one-day tournament in Australia since 1986-87, and were unceremoniously bumped out in the group stages of the World Cup held down under in 2015-16.
But Buttler, who has watched the Ashes while playing for the Sydney Thunder in the Big Bash League, said his side wouldn't have any issues moving on from the Test defeat.
"I think that's the cycle of life," he said.
"Things happen and you move on and they become history and forgotten about. I think the guys will move on pretty quickly and park that disappointment.
"They'll reflect on that themselves. It's a new opportunity. It's a different format and for those guys to potentially free them up and enjoy the one-day aspect of cricket."