Premiership promotion hopefuls London Welsh have announced they will stage their home leg of their play-off final at Oxford United's Kassam Stadium.
The Championship club, who will host Cornish Pirates on 30 May, could adopt Oxford as their home base if promoted.
The Exiles are the only team left in the Championship that could go up.
The club stated last week that they would move their home games away from Old Deer Park if promoted because it is too small to host top-flights games.
A number of venues had been mooted as solutions but the Kassam Stadium, which has a capacity of 12,500, is the first to be confirmed as one of the sites identified by London Welsh as a possible groundshare.
On Monday, Harlequins confirmed that their ground, The Twickenham Stoop, was not one of the sites being considered for a groundshare.
The Exiles are still waiting to have their application to join the English top flight approved whereas their Cornish opponents did not submit a case.
The Rugby Football Union will announce if the London club's submission has successfully passed their minimum standards criteria audit on 21 May.
If it has, and if they win the two legged play-off (the first leg being played in Penzance on 23 May), they will go up.
If neither of the above happens then Newcastle Falcons, who finished bottom of the Premiership pile, will not be relegated.