Justin Rose has withdrawn from the AT&T National which starts on Thursday citing fatigue in the wake of his US Open triumph earlier this month.
The 32-year-old honoured a commitment to play in the Travelers Championship straight after his success at Merion.
But Rose, who won the tournament in 2010, has decided he now needs a break.
"I am disappointed to withdraw but the last three weeks have been extremely demanding for me both mentally and physically," Rose said in a statement.
"This tournament has been very good to me - especially in 2010 - and I would play if I felt I could. I wish I could be there."
The world number three's absence is another blow to the event which supports the Tiger Woods foundation, with Woods having pulled out last week due to an elbow injury.
Rose, who won by two shots in the 113th US Open, has been replaced in the field at the Congressional Country Club in Maryland by American Brendon Todd.