Jason Day withdraws from Players Championship just one hour before scheduled tee-off due to illness

Australian star Jason Day withdrew from The Players Championship an hour before he was supposed to tee off on Friday (AEDT) because of an illness.

Day is No.33 in the world and was coming off a week of contending at the Arnold Palmer Invitational until a double bogey on the 16th hole of the final round ended his hopes.

He won The Players Championship in 2016 when he was the world's No.1 player.

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Day told Australian Golf Digest that a severe stomach bug was the reason for his late scratching.

Day was replaced by Danny Walker, which gives the tournament 26 players who are competing at the TPC Sawgrass for the first time.

Camilo Villegas, Lucas Glover and JJ Spaun are atop the leaderboard after shooting 6-under 66s in the first round at TPC Sawgrass.

"There's always some really good scores and always some really bad scores," Glover said.

"The margins are razor thin here, akin to say Augusta or Bay Hill. You get off just a little, you can make big numbers in a hurry.

"I happened to have a bunch of good numbers today and a bunch of good yardages and was able to be aggressive and I putted great."