Jason Day, Dustin Johnson out of Barclays Pro-Am

Calling it a precautionary measure, No. 2 in the FedEx standings Jason Day withdrew from the Barclays pro-am event with a goal of rest and recovery to be ready for Thursday's first-round tee time with Jordan Spieth and Bubba Watson.

Dustin Johnson also withdrew Wednesday with severe chest congestion.

The opening event of the FedEx Cup playoffs is the first for Day since he won the PGA Championship at Whistling Straits in Kohler, Wisc., August 16.

"Jason tweaked his back moving an item under his motor coach last night. This is a precautionary withdrawal for a long-standing disc issue," said Cornel Driessen, Day's physiotherapist and trainer.

Day is scheduled for an 8:26 a.m. ET tee off Thursday.

Johnson said he is doing everything possible to be ready for his round Thursday.

It comes on the heels of another disappointing finish to a major, when he carded an eight to fall back of the leaders in the final round of the PGA Championship two weeks ago. Johnson also was among leaders at the Open Championship and missed a birdie putt to win the U.S. Open in June.