EDMOND, Okla. — Fred Couples withdrew from the U.S. Senior Open on Thursday because of a back injury, and Craig Stadler and Graham Marsh also pulled out of the event next week at Oak Tree National.

Couples, second in the 2010 tournament, was replaced by John Harris, the first alternate from the Byron, Minnesota, sectional qualifier.

Stadler also cited a back injury, and Marsh, the Australian who won the 1997 U.S. Senior, pulled out because of an undisclosed injury. Stadler was replaced by David Ishii, and Marsh’s spot went to Bruce Vaughan.

Former British Open champion Tom Lehman, meanwhile, will be staying home this time.

Lehman won last week on the Champions Tour, and plans to play at Oak Tree in the U.S. Senior Open next week in Oklahoma. His brother and manager, Jim Lehman, says the former Open champion plans to enjoy a summer vacation with his family for the first time in some 20 years.

Lehman’s son turns 19 the week after the British Open and is off to college the following month.

Lehman won the claret jug in 1996 at Royal Lytham & St. Annes for his only major. He is at No. 7 in the Schwab Cup, having won at the Encompass Championship on June 20. He tied for 20th on Sunday in the Senior Players Championship.