epa08678949 Dustin Johnson of the US hits his tee shot on the seventeenth hole during the second round of the 2020 US Open at Winged Foot Golf Club in Mamaroneck, New York, USA, 18 September 2020. The 2020 US Open will be played from 17 September through 20 September in front of no fans due to the ongoing coronovirus pandemic. EPA-EFE/JUSTIN LANE 
The 36-year-old American, who last competed at September's U.S. Open, has withdrawn from this week's CJ Cup in light of the diagnosis as he begins to self-isolate, the Tour added.
"Obviously, I am very disappointed," Johnson said.
"I was really looking forward to competing this week, but will do everything I can to return as quickly as possible. I have already had a few calls with the Tour's medical team and appreciate all the support and guidance they have given me."
Johnson has had a sensational year, winning his first FedExCup championship at East Lake last month before taking home PGA Tour Player of the Year honours for the second time. (Reporting by Rory Carroll in Los Angeles Editing by Toby Davis and Ken Ferris)