Clarke, who gained entry this week by virtue of his British Open triumph in 2011, pulled out of the field citing a hamstring injury. The Ulsterman's health was already in question entering the week, as he was also forced to withdraw from last week's event in San Antonio with what was termed at the time 'an unspecified leg injury.'
According to a release from his management group, International Sports Management, the injury occurred more than a week ago when Clarke was on vacation in the Bahamas.
'It is with deep regret that I will not be able to play at Augusta this year,' Clarke said as part of the release from ISM. 'Playing in the Masters is one of golf's greatest pleasures and I am very disappointed to be missing out.'
Clarke has yet to regain the form that helped him claim the claret jug at Royal St. George's two years ago, having played just 10 competitive rounds thus far in 2013, all outside the U.S. His last start came at the Tshwane Open in South Africa, where he finished tied for 63rd in early March.
In 11 starts at Augusta National, Clarke has notched only one top-10 finish, a tie for eighth in 1998, and last made the cut in 2006, when he tied for 22nd. He will remain eligible through the 2016 Masters by virtue of his British Open win.
Unlike the other three majors, the Masters has no alternates on standby should withdrawals occur. Instead, the field is reduced to 93 players.