Johnson is currently ranked No. 1 in the world.
Dustin Johnson has withdrawn from the CJ Cup at Shadow Creek in Las Vegas after testing positive for COVID-19, the PGA Tour announced on Tuesday.
After experiencing symptoms, Johnson notified PGA Tour officials and was administered a test. He will now enter self-isolation.
"Obviously, I am very disappointed," Johnson said in a statement. "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."
First alternate J.T. Poston will replace Johnson in the CJ Cup field.
Johnson, the top-ranked player in the world, last competed at the U.S. Open in September, when he finished tied for sixth with Will Zalatoris. The 36-year-old was favored to win in Las Vegas and becomes the second big golfer to contract the virus in two weeks. Tony Finau withdrew from the Shriners Hospitals for Children Open last week after testing positive for COVID-19.
With the Masters only four weeks away, Johnson's positive COVID-19 test could jeopardize his trip to Augusta for the final major in 2020.