Fred Couples has withdrawn from the U.S. Senior Open because of a back injury.
The 55-year-old Couples has a long history of back trouble. He missed the cut at the Masters and has not played in the last two months. Couples also pulled out of qualifying earlier this month for the U.S. Open, held outside his hometown of Seattle.
He was runner-up at the U.S. Senior Open in his first year of eligibility and has not recorded a top 10 in the event since then.
Couples was replaced by Paul Trittler of Cave Creek, Arizona.