Jason Day has withdrawn from the Tour Championship after aggravating his back on Friday afternoon. The world’s No. 1 player, who has a history of back issues, pulled out of the BMW Championship two weeks ago with a similar injury.

The 2015 PGA Champion began the tournament with a first-round 67, and was tied for fifth entering East Lake’s eighth hole. On the tee, Day tugged his drive left into the water. His penalty drop landed in the second cut; from there, Day slashed a driver out of the rough, a move that appeared to trigger the injury.

The WD eliminates Day from FedEx Cup contention, and puts an end to his 2016 season.

UPDATE:

From Day’s management — Jason has a strained ligament in his lower right back with muscle spasm. He withdrew as a precautionary measure. Jason should be fine with some rest after a long break in the offseason.