Bryson DeChambeau and Jon Rahm have joined a long list of athletes who have seen their Olympic dreams crushed by a positive coronavirys test.
World No6 DeChambeau, 27, will be replaced by Patrick Reed after returning a positive test prior to his flight.
The man nicknamed Captain America joins Justin Thomas, Xander Schauffele and recent Open Championship winner Collin Morikawa as part of a formidable Team USA.
DeChambeau, the US 2020 Open winner, said: "I am deeply disappointed not to be able to compete in the Olympics for Team USA.
"Representing my country means the world to me and it was a tremendous honour to make this team.
"I wish Team USA the best of luck in Tokyo. I will now focus on getting healthy and I look forward to returning to competition once I am cleared to do so."
Meanwhile, Spain will send world No199 Jorge Campillo in place of leading hope and world No1 Rahm, who suffered the same cruel fate only last month when forced to withdraw from the PGA Tour’s Memorial Tournament after three rounds.
On that occasion, Rahm held a six-shot lead going into the final day — effectively losing out on around £1.2million by not being able to close out a seemingly certain victory.
Despite having been vaccinated seven weeks ago, the 26-year-old will once again have to watch the action unfold from afar while serving a period of isolation.
Rahm said: "I've been fortunate to represent my country and win a championship for Spain around the world as an amateur.
"Playing in Tokyo would have given me the chance to win an Olympic gold medal for my country.
"I would have loved to have been the first Spanish Olympic gold medallist in golf but unfortunately destiny had other plans.
"This is a great reminder for us all that we are still in a pandemic, things are not over, and we still need to fight together to get through this the best we can."
Kasumigaseki Country Club plays host to the golf competition, which follows the reintroduction of the sport to the Games in 2016 after a 112-year hiatus.
It was Team GB’s Justin Rose who took the gold medal in the men’s competition five years ago but Tommy Fleetwood and Paul Casey will carry British hopes in Japan.
The men's competition begins on Thursday and runs for four days, with the women's event starting on Wednesday, August 4.
Champ and Elvira in winner’s circle
In a week where many of the game’s bigger stars have been bound for Japan or enjoying some post-Open rest, Cameron Champ and Nacho Elvira took full advantage to secure unlikely wins on their respective tours.
For Champ, 26, it was a third career PGA Tour success — winning the 3M Open after overcoming dizziness and dehydration to shoot a final round of 66, which was enough to prevail by two strokes.
Victories in 2018 and 2019 mean the Texan is a known commodity to fans but few could have forecast his performance this week after what has been an incredibly tough period.
Arriving at TPC Twin Cities ranked 142nd in the FedEx Cup standings and without a top-10 finish since October 2020, Champ turned the form book on its head to lift the title.
A gutsy par save on the final hole having gone wildly left off the tee was a fitting way for him to close out a tournament where he had to show tremendous guts.
Champ said: "Coming down the stretch I felt very calm, very relaxed and kind of in my zone.
"Obviously 18 made it a little interesting. I felt like I hit a great second shot from where that lie was, hit a great approach there and made the putt."
If Champ’s win was a surprise, Elvira’s was gobsmacking.
The 34-year-old Spaniard is a relative veteran of the European Tour but arrived at the Cazoo Wales Open winless in 194 starts.
There have been close shaves, having been a runner-up on three occasions including two heart-breaking play-off defeats — making the nature of his maiden success all the more impressive.
Heading into Sunday at Celtic Manor with a scarcely believable six-shot lead, Elvira saw his margin slowly evaporate throughout the course of Sunday before a final-hole bogey forced him into a play-off with in-form South African Justin Harding.
Momentum and logic suggested another chance had came and gone for Elvira but a dramatic three-putt from Harding on the first extra hole earned him the most glorious of reprieves.
Elvira said: "It means the world That’s what we practice for and what we strive for.
"We try to win, to be at the best level on the European Tour and play with the best. It means the world to me.
"I'm speechless right now, to be honest. I thought I had it all pretty under control but I got pretty nervous on the last couple of putts on the regular 18.
"I was more calm in the play-off than I was on the 18th.
"It's a shame to see someone miss a putt, I suppose they felt the same for me when I missed but I can't believe I won."
He reserved the final word for his legendary late countryman Seve Ballesteros, who inspired him to take up the game as a youngster.
Elvira added: "I hope Seve, wherever he is, I hope he's proud."