Defending champ Dufner out of PGA Championship

Louisville, KY ( - Defending champion Jason Dufner withdrew from the PGA Championship after 10 holes on Thursday with neck issues.

Dufner was recently diagnosed with two bulging discs in his neck, and he has contemplated skipping the FedExCup playoffs in order to be healthy for the Ryder Cup at the end of September.

The three-time winner on the PGA Tour had fallen to 8-over par through 10 holes at Valhalla after making a triple-bogey on his 10th.

Dufner stumbled out of the gate to a double-bogey at the first. He followed with bogeys at two and three to slide to plus-4. After a pair of pars, Dufner tripped to a bogey on the sixth.

He parred the last three holes of his opening nine. Around the turn, Dufner stumbled to a triple-bogey on No. 10. He then took his hat off and shook his playing partners hands and left the course.

Along with winning last year, Dufner was the runner-up in 2011. He lost to Keegan Bradley in a playoff that year at Atlanta Athletic Club.