Former World No. 1, Australian golfer Adam Scott has tested positive for COVID-19 and pulled out from this week's PGA Tour event in California.

The PGA Tour confirmed in a statement on Thursday (AEST) that Scott has withdrawn from the Zozo Championship after his positive test.

"Scott who last competed at the U.S. Open in September, will have the PGA Tour's full support throughout his self-isolation period under CDC guidelines," it said.

"First alternate Jim Herman will replace Scott in the field."

Scott is currently ranked No.15 in the world and remains the only Australian to have won the Masters Tournament, back in 2013.

"While it's difficult news to receive, as I really looked forward to playing this week, my focus now is on recovery for the final stretch of the fall," Scott said in a statement.

He has not played since the US Open, and has played only four times - two majors and two FedEx Cup playoff events - in the four months since the PGA Tour returned from the COVID-19 shutdown.

Scott is the third player from the top 20 to have tested positive in recent weeks, including world No.1 Dustin Johnson, who was diagnosed last week at the CJ cup in Las Vegas.