Jason Dufner, who won the 2013 PGA Championship at Oak Hill for his lone major title, withdrew from this year's edition at the same venue, the PGA of America announced on Friday.
No reason was provided for Dufner's withdrawal. He missed the cut at this week's AT&T Byron Nelson. Sweden's David Lingmerth replaced him in the field.
Also withdrawing ahead of the championship was two-time major winner Martin Kaymer. His absence reduces the number of LIV Golf players in the PGA Championship field to 17. He was replaced by Callum Tarren. Eric Cole is now the first alternate.