The 36-year-old American, who last competed at September’s U.S. Open, has withdrawn from this week’s CJ Cup in light of the diagnosis as he begins to self-isolate, the Tour added.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.