Padraig Harrington has withdrawn from the AT&T Pebble Beach Pro-Am after testing positive for Covid-19.
The Ryder Cup captain took part in the Phoenix Open last week and had been poised to compete in his fourth PGA Tour event of the season before the diagnosis.
The Dubliner will now undergo a period of self-isolation under American CDC guidelines.
He has to undergo a ten-day quarantine and has not yet ruled himself out of the Genesis Invitational at Riviera Country Club in Los Angeles next week.
After that event, he has a week off before hopefully heading to Florida for the Arnold Palmer Bay Hill Invitational.
Harrington's caddy Ronan Flood tested negative for the virus but is a close contact so they are isolating in separate hotels.
The three-time major winner took part in the Waste Management Open in Phoenix last week and had been poised to compete in just his second PGA Tour event of the year, having also played on the European Tour in Abu Dhabi and Dubai, where he had enjoyed his best tournament performance in over two years finishing in a tie for sixth place.
Korean golfer Bae Sang-moon will take Harrington's place at Pebble Beach.
World number one Dustin Johnson, fresh off his triumph at the European Tour's Saudi International, has also withdrawn from this week's event.
Johnson, whose latest win marked his ninth European Tour title, felt it would be best to enjoy a week at home before competing at the Genesis Invitational and the World Golf Championships at The Concession.
Even before Harrington's withdrawal, the Pebble Beach event has had to make changes due to the pandemic with the Pro-Am portion of the tournament cancelled due to Covid-19 protocols.
Instead of being contested across three courses this year, the event will take place at Pebble Beach and Spyglass Hill, with the cut falling after 36 holes instead of 54.