The world No. 2 and defending champion here has been bedridden for the past few days and confirmed in a text to the AAP on Tuesday that he was “sick as a dog.”
Day has played only one stroke-play event since Sept. 27, a tie for 10th earlier this month at the Tournament of Champions.
His first-round tee time is 9:20 a.m. local time, off Torrey Pines' North Course. He is grouped with J.B. Holmes and Harris English, whom he defeated in a playoff last year.
The last time Day skipped a pro-am because of injury or illness, at The Barclays, he went on to win.