However, PGA Tour officials said they still expect Day to tee off in Thursday's opening round at Torrey Pines as planned, from the 10th tee on the North Course.
Day, who enjoyed a career-best season on the PGA Tour last year that included his first major title at the PGA Championship among five wins, has been eagerly anticipating his title defence at Torrey Pines.
"(I'm) looking forward to getting back under way and trying to defend this tournament, which is very special to me," Day told reporters at the Farmers Insurance Open media day. "That kind of catapulted my year to turning the way it did."
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Day, 28, heads a strong field at Torrey Pines this week where five players in the world's top 10 are scheduled to compete, including fourth-ranked American Rickie Fowler and seventh-ranked Englishman Justin Rose.
(Reporting by Mark Lamport-Stokes in Los Angeles; Editing by Frank Pingue)
