Clarke lasted only six holes in last week's Players Championship

The injury forced Clarke to pull out of last week's Players Championship after only six holes of the opening round.

Clarke, who suffered the injury while playing football with his children, is hoping to be fit for next week's BMW PGA Championship.

"I so wanted to compete for Ireland's national title," said Clarke, who has dropped to 85th in the world rankings.

The 38-year-old Northern Irishman was told that that unless he rests and has further intensive treatment he could do more damage.

After sustaining the injury, Clarke missed the cut in the Spanish Open, then flew to America only to pull out of the Wachovia Championship after one round before his brief outing at the Players Championship.

Scans revealed that the problem is at the top of his right hamstring and he added: "To say I'm disappointed is putting it mildly so this is another blow on top of many recent frustrations.

"If I had played this week, I would have risked further damage and probably turned it into a long-term injury.

"Now I have the chance of being fit to return at Wentworth next week for the BMW PGA Championship.

"I feel gutted not to play in the Irish Open, especially after coming so close last year (he finished third after leading with nine holes to play).

"I'm really down in the dumps after so many recent setbacks, but I have to make sure I get fit as soon as I possibly can."

Clarke was unbeaten in last September's Ryder Cup win after being picked by captain Ian Woosnam only three weeks after his wife Heather lost her battle with breast cancer.

He has had nothing better than a 20th place finish all year and has not made a cut since early February.