Tyrrell Hatton, Sergio Garcia and Louis Oosthuizen have decided not to compete at the Olympics in Tokyo this summer.
The Summer Games are set to go ahead - having been postponed last year due to the coronavirus pandemic - but the trio have decided against taking part in the golf tournament.
Lee Westwood and Matt Fitzpatrick have both turned down the chance to represent Team GB at the Olympics, so their second allocated spot now goes to Tommy Fleetwood - originally the third alternate - who will join Paul Casey in Japan.
World No 11 Hatton wrote on Twitter: "I have decided after much thought and consideration to step down from Team GB for the forthcoming Olympics this summer in Tokyo.
"I was very much looking forward to representing my country. However, with the ongoing issues relating to Covid-19 and international travel, along with the congested schedule we now face, I feel it is the correct decision to ensure I get the best out of my game for the remainder of the season."
Former Masters champion Garcia is a Ryder Cup legend and feels he should concentrate on this year's USA v Europe showdown, to be held in September in Wisconsin.
The Spaniard posted: "I have made one of the most difficult decisions in my life.
"I love the Olympics Games and it is always an honour to represent Spain, however my number one sporting priority is in the Ryder Cup at this moment.
"Everyone knows what the Ryder Cup means to me.
"My number one objective is to qualify for the European team by my own merit and not have to wait for a possible invitation."
South African Oosthuizen is in the midst of a fine run of form, finishing second to Jon Rahm in the US Open on Sunday.
Oosthuizen wrote: "Qualifying for the Olympics is a humbling accomplishment and there's no greater honour than representing your country, so it has been a very difficult decision for me, my team and my family to withdraw from playing in Tokyo.
"I am focused on finishing a strong Fed Ex Cup season in the States, in addition to honoring family commitments with the new life we are building at the farm. Family has always been my core and this is the best decision for us at this time in our lives.
"My best are with the South Africans competing. We will be cheering you on!"