Welshman Jamie Donaldson withdrew from the PGA Championship before the start of Friday's second round due to a back injury, tournament organisers said.

The 37-year-old had battled to a 10-over-par 80 at Oak Hill Country Club on Thursday.

Donaldson, who won the second European Tour title of his career at the Abu Dhabi Championship earlier this year, was making his third appearance in the season's final major.

His best PGA Championship finish was a tie for seventh at Kiawah Island last year.