Day was playing in pain all day, struggling with a back injury that he said flared up Thursday. It’s the latest physical malady for the Australian in a frustrating season full of them.
“I am extremely disappointed to have to pull out of the event,” Day said in a statement. “I will be getting treatment on my back over the next few days and hopefully be ready for the Tour Championship.”
Day told Australian AP on Thursday that his back has been bothering him lately and that it “seized up” on him in the first round.
Despite a thumb injury, a recurring throat infection and a battle with vertigo, Day has put together a surprisingly strong season. He entered the BMW Championship seventh in FedEx Cup points. He’s qualified to play the Tour Championship in Atlanta next week, but whether he’s physically able is still unclear.
After winning the WGC-Accenture Match Play Championship in February, Day missed nearly two months with a thumb injury. He made just two starts between his match play victory and the U.S. Open in June and still tied for fourth at Pinehurst No. 2. He withdrew from the WGC-Bridgestone with vertigo last month and now has the back injury to contend with.