Chief executive Richard Holland has admitted Cardiff Blues may not return to play home games at the Arms Park before Christmas.
The ground became part of the Principality Stadium field hospital complex in March dealing with Covid-19.
The Cardiff and Vale University Health Board decommissioned the site earlier this month.
But the ground is not ready for use immediately because of damage to the artificial pitch surface.
Holland told a supporters Q+A on Wednesday, 7 October inspections of their pitch showed it would need to be replaced.
"Unfortunately, due to the longevity of the generators and the marquees and everything else that went into supporting the hospital it has done some damage to the pitch which means we are going to have to put a new surface in," Holland explained.
"As it stands all of our fixtures until the end of November will be played at Rodney Parade.
"We are waiting for our suppliers to give us a timeline and it may be until the end of December that we're not able to get on the Arms Park.
"The only positive is that the surface at Rodney Parade is fantastic. It's not ideal but we will be back there on a new artificial surface and that process will start in the coming weeks."
Blues played their final home match of the 2019-20 season against Ospreys at Rodney Parade in Newport, which is the home of Welsh regional rival Dragons.
The same venue also hosted Blues' 2020-21 season opener against Connacht on October 10.
Blues are now due to host Ulster on 2 November, Benetton on 16 November and Glasgow on 29 November at Rodney Parade.
One Challenge Cup home match is scheduled for December before home derbies against Ospreys and Scarlets in early January.
Head coach John Mulvihill hopes his side can return to play home games at the Arms Park before Christmas.
"Our home is the Arms Park and we want to get back there," said Mulvihill.
"We will get back there when it's safe for the fans and players to play on that surface, so hopefully that will be before Christmas which would be great.
"History shows the grass does not grow very well because of the nature of where it is.
"If we want to get a good, fast game, a plastic pitch is good for us and we seem to enjoy it."