Tiger Woods has admitted that he doesn't know when he will be fit enough to return to competitive golf action.

The world number one had to sit out last month's Masters, the first time he has missed the Major at Augusta, because of a back injury and is hoping for a return at some point this summer.

"I'm doing everything I can and listening to my doctors and working on a strength program, and then we just have to see how my back is," he wrote on his website.

"Some people heal up in three months, some people take four months, some people take longer. I just don't know."

Woods said that he has his eye on possibly taking part in the three remaining Majors and then the Ryder Cup at Gleneagles in the autumn.