Jordan Spieth’s decision to forgo next month’s Rio Olympics assures that golf’s return to the Games after a 112-year absence will proceed without the winners of four of the past six men’s majors and the last four players to hold the world No. 1 ranking.

Spieth, 22, a two-time major winner, joined the current world No. 1 Jason Day of Australia, Day’s countryman Adam Scott and Rory McIlroy of Northern Ireland on the sideline. Spieth, whose initial enthusiasm for representing Team U.S.A. led him to be featured in NBC and Golf Channel promotional spots, notified officials with the International Golf Federation of his decision ahead of a midnight deadline Monday.

Eighteen of the eligible men, based on the world rankings, have withdrawn. Only one woman, the 39th-ranked Lee-Anne Pace of South Africa, has bowed out, citing fears about the mosquito-borne Zika virus.

The third-ranked Spieth became the second American men’s golfer, after the world No. 2 Dustin Johnson, to withdraw from the Summer Games, citing health concerns related to the Zika virus. In the absence of Johnson and Spieth, the United States team will consist of No. 5 Bubba Watson, No. 7 Rickie Fowler, No. 13 Patrick Reed and No. 15 Matt Kuchar, who secured his passage to Rio with a closing 66, good for a tie for third, in his last competitive start, Ohio’s Bridgestone Invitational, which moved him into the top 15 in the world rankings.