Tiger Woods isn't the only big-name golfer battling a sore arm.
Daly tweeted late last week that he tore a tendon at the Greenbrier Classic and will have surgery in the next few days. He expects to be out of action for three months or longer.
His injury dates to the Byron Nelson Championship in May. Doctors told him he could continue playing as long as he didn't hit a rock or a tree root.
"That's what happened on the 12th hole Friday at Greenbrier," he told reporters. "I was just trying to chip out and there was a root under the ball. It wasn't more than a 50-yard chip shot, but that's the pain I've been dealing with."
Stephen Gallacher of Scotland will replace him at Muirfield when play begins July 18.
Daly automatically qualifies for the tournament as a past champion.