The England and Wales Cricket Board will meet this week to decide whether the men's Ashes tour of Australia this summer will go ahead.
Root and Paine Photo: PHOTOSPORT
England players were presented with the proposed conditions for the tour on Sunday evening.
Some have concerns over whether families can travel, quarantine arrangements and any potential 'bubble' they may have to live in.
The first Test begins on 8 December and the series is due to end on 18 January.
An ECB statement read: "The board will decide whether the conditions are sufficient for the tour to go ahead and enable the selection of a squad befitting a series of this significance."
Australia has some of the strictest Covid-19 protocols in the world, a situation complicated by the fact its different states have their own regulations.
The five Ashes Tests are due to played in five states.
Any England players who take part in the T20 World Cup and the Ashes face being away from home for about four months.
The squad for the World Cup, which takes place in the United Arab Emirates and Oman from 17 October to 14 November, leaves on Monday.
It means that some players leave for that tournament without knowing when they will return.
The red-ball specialists are not due to leave for Australia until early November.
England are already without fast bowler Jofra Archer with an elbow injury, while all-rounder Ben Stokes could miss the tour as he takes an indefinite break from the game to protect his mental wellbeing.
The tourists are due to name an enlarged squad, with an England Lions team set to be in Australia during the Ashes series.
Last week, England captain Joe Root said he was "desperate" to be part of the tour, but stopped short of committing to take part.
Australia skipper Tim Paine said: "The Ashes are going ahead. The first Test is on 8 December - whether Joe is here or not."
He told radio station SEN Hobart: "It'll be worked out above us and then they'll have a choice whether to get on that plane or not.
"No-one is forcing any England player to come. That's the beauty of the world we live in - you have a choice. If you don't want to come, don't come."
1st Test, Brisbane, Dec 8-12
2nd Test, Adelaide, Dec 16-20
3rd Test, Melbourne, Dec 26-30
4th Test, Sydney, Jan 5-9
5th Test, Perth, Jan 14-18.
-BBC
