Two-time winner Greg Norman has withdrawn from the Open Championship at Royal Liverpool starting on 20 July.
Norman will also miss the Senior British Open
The 51-year-old Australian had surgery on his right knee in February and had hoped to play at Hoylake.
But his return to action is not likely to be before August now, meaning he will also miss this week's US Seniors Open and the Senior British Open.
Norman will be replaced by last season's European Tour rookie of the year Gonzalo Fernandez-Castano.
"My knee is fine," said Norman. "My game just isn't where I want it to be and the last thing I want to do is take a spot away from another deserving professional.
"Now I can focus on my game and get ready to play some tournaments later this summer."
Norman won the Open at Turnberry in 1986 and Sandwich in 1993 and made the cut at St Andrews last year in his first tournament after a back operation in March.
He was then third in the Senior British Open at Royal Aberdeen, but was back in hospital for knee surgery in October.