The world number one will be using the courts in Santa Ponsa.
It was only 13-time champion Nadal's third defeat here since his debut in 2005.
Is this a good strategic move for RCD Mallorca? Monro Bryce's views
Spanish players fear possible side effects.
The team's preparations for Euro 2020 were thrown into disarray by two players testing positive for the virus.
Novak Djokovic predicted a "great battle" when he continues tennis's most prolific rivalry against claycourt king Rafa Nadal.
Spain's players have been in isolation and only able to train on an individual basis.
The squad and coaching staff immediately went into isolation following Busquets' positive test.
Spain are due to face Lithuania in a friendly on Tuesday with their Under-21 squad
Monro Bryce's thoughts on RCD Mallorca's return to the Spanish top league.
How does an athlete feel after a defeat? The experiences of former Olympic swimmer James Parrack.