Rahm, who arrived at the PGA Tour's flagship event seeking his fourth win of the season, opened with a one-under-par 71 on Thursday that left him seven shots behind first-round leader Chad Ramey.
The Spaniard, who entered the week having finished in the top 10 in six of his seven starts on the PGA Tour this season, had been scheduled to tee off at 12:56 (17:56 GMT) alongside fellow major champions Scottie Scheffler and Rory McIlroy.