Second seed Daniil Medvedev was on Tuesday withdrawn from the Monte Carlo Masters after testing positive for COVID-19.
The ATP confirmed the Monday result and said the Russian would now be isolated at his Monte Carlo residence.
“It’s a big disappointment not to play in Monte Carlo,” the world No. 2 said in a statement.
“My focus is now on recovery and I look forward to getting back out on Tour as soon and as safely as possible.”
The ATP said Medvedev “has been moved into isolation and continues to be monitored by the Tournament Physician and ATP Medical Team.”
The Russian who lost the Australian Open final to Novak Djokovic will be replaced for his second-round match (after a bye) and was also automatically pulled from doubles.
Medved had been due to open the week against the winner from Serb Filip Krajinovic and Nikoloz Basilashvili of Georgia.