There will be no more internationals at the Principality Stadium this year, Welsh Rugby Union chief executive Martyn Phillips has confirmed.
The ground has been converted into the temporary Dragon's Heart Hospital.
The WRU expects to sign a new contract to keep it in place as a medical facility in case of a second coronavirus spike.
"We will not be playing any home games at Principality Stadium," confirmed Phillips.
The WRU is in negotiations with the Welsh Government and Cardiff and Vale University Health Board to keep the temporary hospital in place until autumn, and then have the stadium back as a rugby venue for the 2021 Six Nations.
"Our decision to step in to provide a location for a surge hospital at the height of the pandemic, along with the scale of the investment to construct the Dragon's Heart Hospital in the stadium, has meant we have agreed in principle to extend the hospital until the autumn," said Phillips.
"We have yet to finalise a contract on the extension, as this time it is a little more complex and there are a number of circumstances that need to be covered. We hope to sign the contract shortly.
"On a more optimistic footing, we plan to be back playing at the Principality Stadium - hopefully in front of full crowds - against England and Ireland in the Six Nations in February 2021."
Phillips outlined the discussions about where the matches will be played, with London venues and regional grounds being considered depending on whether crowds will be allowed into stadiums.
"Assuming games are staged this autumn, if restrictions mean we are playing behind closed doors those games are likely to be staged in Wales and we are exploring a range of options," said Phillips.
"If the games can be staged with crowds in some form those games are likely to be in and around London and, again, we are exploring a range of options.
"The most difficult scenario will be if games are allowed with crowds in England but not in Wales.
"There are clearly a range of risks here, not least Welsh fans leaving Wales to attend a game and then returning. Clearly this risk also occurs for away games.
"We very much hope by the autumn that restrictions, whatever they be in relation to sports events, are aligned across the UK."
Wales were due to be playing the rearranged Six Nations match against Scotland on 31 October in Cardiff, before an autumn series against South Africa, New Zealand, Fiji and Argentina.
The Scotland Six Nations fixture should still stand for the same date, but the autumn programme is in line to be replaced by a tournament involving the Six Nations sides and two countries out of Fiji, Japan and Georgia between 14 November and December 5.
"The reality is we continue to juggle a number of unknowns," said Phillips.
"While we expect to replay our postponed Six Nations 2020 fixture with Scotland, the competition format and opposition for additional autumn games are yet to be agreed.
"We hope for news on these fixtures in the coming weeks."
The WRU also announced it will now be processing refund, credit or donate options for supporters for Wales' postponed 2020 Six Nations match with Scotland on 14 March.
Supporters have three options; to be refunded using the 'credit my account' option, which will enable priority for them to buy tickets for the rescheduled fixture when it is announced subject to crowds being permitted, choose a direct refund to the card that bought their ticket or donate the ticket value to the WRU.