Former world number one Adam Scott has pulled out of this week's Zozo Championship in California after testing positive for coronavirus.
The PGA Tour confirmed on Wednesday that the 40-year-old Australian will not play at the Sherwood Country Club.
Scott said his "focus now is on recovery" for the rest of the season.
In a statement, the PGA Tour said Scott "will have the PGA Tour's full support throughout his self-isolation period under CDC guidelines".
American Phil Mickelson is playing in California, but says he is considering missing next month's Houston Open, where a limited number of fans are set to be allowed in.
"For me personally, I don't like the risk that having that happen the week before the Masters," said Mickelson.
"I just don't want to have any risk heading in there, It has made me question whether or not I'll play there.
"But I have to give the Tour a lot of credit and confidence in the way that they've handled the entire year and I'm sure they're going to do a great job at keeping the players safe in that environment."