Rahm birdied his opening hole in the first round before slumping to a six-over-par 76.
The overnight weather forecast proved accurate ahead of the second major of the year.
Rahm has won four times in 11 events in 2023, the most recent seeing him replace Scottie Scheffler as world number one after winning the ...
The four-time major winner missed the cut at Augusta National last month.
American players remain eligible for the biennial contest despite being banned or resigning from the PGA Tour.
The renovated East Course at Oak Hill is set to provide the world’s best players with a severe test.
The last seven men’s majors have been won by players in their 20s.
The 30-year-old has experienced a testing season.
The pair are vying for favouritism ahead of the US PGA Championship at Oak Hill.
McIlroy felt the break was necessary for his “mental and emotional wellbeing” after a taxing 12 months.
